Polymer conjugate for delivery of a bioactive agent

ABSTRACT

The present invention relates in general to polymer-bioactive agent conjugates for delivering a bioactive agent to a subject. The polymer-bioactive agent conjugates contain triazole moieties in the polymer backbone and a bioactive moiety comprising prostaglandin analogues. The present invention also relates to methods for preparing the polymer conjugates using click chemical reactions, to monomer-bioactive agent conjugates suitable for preparing the polymer conjugates, and to pharmaceutical products comprising the polymer conjugates for the treatment of glaucoma.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. application Ser. No.15/435,784, filed Feb. 17, 2017, which is a continuation of U.S.application Ser. No. 14/772,981, filed Sep. 4, 2015, now U.S. Pat. No.9,572,892, which is the U.S. national stage of PCT/AU2014/000231 filedMar. 7, 2014, which claims priority to Australian Application2013900883, filed Mar. 8, 2013, the entire contents of each of which areincorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates in general to polymer-bioactive agentconjugates for delivering a bioactive agent to a subject. In particular,the present invention relates to polymer-bioactive agent conjugatescontaining triazole moieties in the polymer backbone for delivering abioactive agent selected from prostaglandin analogues and β-blockers.The present invention also relates to methods for preparing the polymerconjugates by means of alkyne/azide cycloaddition reactions (“clickchemical reactions”), to monomer-bioactive agent conjugates suitable forpreparing the polymer conjugates, and to pharmaceutical productscomprising the polymer conjugates for the treatment of glaucoma.

BACKGROUND

Polymer-bioactive agent conjugates containing a bioactive agentcovalently bound to a polymer are of interest for the targeted andcontrolled delivery of therapeutic agents. In the treatment of manydifferent conditions, the site-specific delivery of a drug directly toor near a desired site of action in the body of a subject can be highlydesirable to improve the efficacy and/or safety of the drug. Certainsites in a subject may require sophisticated delivery vehicles toovercome barriers for effective drug delivery. For example, the eye hasa limited volume for administration and requires a pharmaceuticalproduct with a high drug loading to ensure that adequate doses of drugcan be delivered while keeping product volume to a minimum. Despite thelimited volume it is desirable to be able to deliver drug to the sitecontinuously and in a controlled manner over an extended period of time.

β-blockers are antagonists of beta-adrenoreceptor sites and are used totreat or manage a range of conditions, including cardiac arrhythmias,hypertension, hypotension and glaucoma. Elevated intraocular pressure(ocular hypertension) is a risk factor for glaucoma. β-blockers canreduce intraocular pressure and exert an ocular hypotensive effect byreducing the production of aqueous humour in the eye.

Prostaglandin analogues are molecules designed to bind to aprostaglandin receptor and are used to treat gastro-intestinal acidrelated disorders such as duodenal and gastric ulcers, as abortifacientsor uterotonics to induce labour or prevent past partum haemorrhage, andto treat ocular hypertension. Prostaglandin analogues exert an ocularhypotensive effect by increasing uveoscleral outflow of aqueous humour.

Prostaglandin analogues and β-blockers used in the treatment of glaucomaare presently formulated as eye drops, which if administeredconscientiously to the affected eye will lower intraocular pressure.This in turn can slow the progression of glaucoma. The prostaglandinanalogues and β-blockers are administered as eye drops, either alone(i.e. as a single agent) or in combination. It is postulated thatcombining prostaglandin analogues with β-blockers that exert theireffect through a different mechanism, may provide an additive effect inreducing intraocular pressure. For example, some pharmaceuticalpreparations used in the treatment of glaucoma, such as Xalacom™ eyedrops marketed by Pfizer and Ganfort™ eye drops marketed by Allergan,contain a prostaglandin analogue in combination with a β-blocker.

Unfortunately, as glaucoma is an asymptomatic disease many patients donot use their drops conscientiously, compromising therapy. A recentstudy by Friedman et al. (Friedman et al. IOVS 2007:48, 5052-5057)showed that adherence to glaucoma treatment options is poor with only59% of patients in possession of an ocular hypotensive agent at 12months, and only 10% of patients used such medication continuously.Patient compliance in glaucoma therapy is therefore an issue.

Drug delivery systems have been developed to aid in the administrationand/or sustained delivery of bioactive agents (such as drugs) to adesired site of action. One mode of delivering a drug to a subjectinvolves the use of a polymer in association with the drug so that itcan be delivered to and/or retained at a specific location.

One form of a polymer/drug delivery system utilises an admixture of apolymer with a drug, where the drug is blended with the polymer matrix.However, such admixtures generally result in poor control over therelease of the drug, with a “burst effect” often occurring immediatelyafter administration and significant changes in the physical propertiesof the admixture occurring as the drug is released (Sjoquist, B.; Basu,S.; Byding, P.; Bergh, K.; Stjernschantz, J. Drug Metab. Dispos. 1998,26, 745). In addition, such admixtures have limited dose loadingcapacity, resulting in a prohibitively large device for convenientadministration to some sites in a subject.

Another form of a polymer/drug delivery system is based on thepolymerisation of a drug so as to incorporate the drug molecule as partof the backbone of a polymer chain. Such a system is described in U.S.Pat. No. 6,613,807, WO2008/128193, WO94/04593 and U.S. Pat. No.7,122,615. However, such polymer systems generally provide inefficientdelivery of the drug, as release of the drug relies on breakdown of thepolymer backbone. Furthermore, breakdown of the polymer backboneproduces inactive intermediates. Such intermediates can complicateregulatory approval, which may require the safety of the intermediatesto be demonstrated.

Another approach for preparing polymer-bioactive agent conjugatesinvolves the covalent attachment of bioactive agent molecules to apre-formed polymer backbone. Examples of such polymer conjugates havebeen reviewed in Nature Reviews: Drug Discovery 2003:2, 347-360.However, this approach can also be problematic. In particular, stericand thermodynamic constraints can affect the amount of bioactive agentthat can be covalently attached, and also impact on the distribution ofthe bioactive agent along the polymer backbone. These factors can, inturn, reduce control over the release of the bioactive agent.Furthermore, the use of a pre-formed polymer backbone provides limitedscope for modification of the polymer conjugate after attachment of thebioactive agent should the properties of the conjugate need to beadjusted to improve drug release and/or to aid patient comfort,particularly in the eye.

For efficient delivery, bioactive agents such as drugs are ideallypendant from the backbone polymer chain.

In preparing polymer-bioactive agent conjugates, step-growthpolymerisation is one approach that has been used. By means ofstep-growth polymerisation, polymer-bioactive agent conjugates can beprepared by covalently reacting a bioactive agent-functionalised monomerhaving at least two terminal reactive functional groups, with aco-monomer of complementary terminal functionality. An example is thereaction of a drug-functionalised dihydroxy monomer with a diisocyanateco-monomer to form a polymer-drug conjugate with a polyurethane polymerbackbone. However, one problem with step-growth polymerisation methodsis that many bioactive agents, such as drug molecules, can containmultiple functional groups that are capable of participating in thecovalent reactions used to form the polymer. In such circumstances,there is a risk that a functional group on a drug molecule could reactwith a terminal functional group of a monomer, leading to intra-chainincorporation of the bioactive agent in the polymer. As a result, thebioactive agent becomes part of the polymer backbone structure, ratherthan forming a pendant group. Prostaglandin analogues and β-blockers areexamples of such drugs with multiple nucleophilic functional groups witha consequential high risk of in-chain incorporation.

It would be desirable to provide new polymer-bioactive agent conjugates,which address or ameliorate one or more disadvantages or shortcomingsassociated with existing materials and/or their method of manufacture,or to at least provide a useful alternative to such materials and theirmethod of manufacture.

SUMMARY OF THE INVENTION

The present invention provides in one aspect, a polymer-bioactive agentconjugate comprising a polymer backbone comprising a plurality oftriazole moieties, and a plurality of releasable bioactive agentscovalently bonded to and pendant from the polymer backbone, wherein thebioactive moieties comprise prostaglandin analogues covalently bonded toand pendant from the polymer backbone from the 1-position of theprostaglandin analogue via an ester linking group.

Polymer-bioactive agent conjugates of the invention are obtained throughthe use of click chemistry, in particular through the application ofvariants of the Huisgen 1,3 dipolar cycloaddition of azides and alkynes.With click chemistry, at least two co-monomers of appropriatecomplementary terminal functionality covalently react to form thepolymer-bioactive agent conjugate. At least one of the co-monomerscarries a pendant bioactive agent. The triazole moieties present in thepolymer backbone of the polymer-bioactive agent conjugate are reactionproducts obtained from the covalent coupling of terminal functionalgroups present on the co-monomers. Thus, the covalent reaction betweenthe co-monomers results in the formation of a polymer-bioactive agentconjugate comprising a polymer backbone and bioactive agents pendantfrom the polymer backbone, together with triazole moieties in thepolymer backbone structure.

In some embodiments, polymer-bioactive agent conjugates of the inventioncomprise a moiety of formula (I):

where:

T at each occurrence represents a triazole moiety;

Q is independently selected at each occurrence and may be present orabsent and when present represents a linking group;

R is an optionally substituted linear or branched hydrocarbon and maycomprise optionally substituted aromatic hydrocarbon or heteroaromatichydrocarbon

Z is a cleavable linking group; and

D is a releasable bioactive agent.

In some embodiments, polymer-bioactive agent conjugates of the inventioncomprise a moiety of formula (Ib):

where:

T at each occurrence represents a triazole moiety;

Q is independently selected at each occurrence may be present or absentand when present represents a linking group;

R is an optionally substituted linear or branched hydrocarbon and maycomprise optionally substituted aromatic hydrocarbon and orheteroaromatic hydrocarbon;

Z¹ and Z² are each cleavable linking groups that may be the same ordifferent; and

D¹ and D² are each releasable bioactive agents that may be the same ordifferent.

In formulae (I) and (Ib), the bioactive agent comprise prostaglandinanalogues.

Triazole moieties present in the polymer backbone of thepolymer-bioactive agent conjugates, which are the product of anazide/alkyne coupling, are 1,2,3-triazole moieties.

In some embodiments, the polymer backbone of the polymer-bioactive agentconjugate comprises at least one triazole moiety selected from the groupconsisting of formula (II), (III) and (IX):

wherein in formula (IX), A represents an optionally substituted cyclicgroup, preferably a cyclic group comprising from 7 to 9 ring atoms.

In some embodiments, the polymer-bioactive agent conjugate comprises atleast one moiety selected from formula (IIa) and (IIb):

In some embodiments, the polymer-bioactive agent conjugate comprises atleast one moiety selected from formula (IIIa) and (IIIb):

In one set of embodiments the triazole unit T is of formula IV

wherein:

either

A. one of R^(v) and R^(z) is (Q) and the other is hydrogen; or

B. R^(v) and R^(z) together complete a ring of from 7 to 9 constitutentring members selected from the group consisting of carbon and from 0 to2 heteroatom groups selected from sulfur and the group N—R^(t) whereinR^(t) is hydrogen, C₁ to C₆ alkyl or the group (Q) and wherein the ringis optionally substituted with at least one substituent selected fromthe group consisting of:

hydroxyl (preferably from 0 to 2 hydroxy);

oxo (i.e. ═O) (preferably 0 or 1 oxo group);

halo (preferably from 0 to 2 halo selected from chloro, bromo and fluoroand most preferably fluoro);

C₁ to C₆ alkoxy (preferably from 0 to 2 C₁ to C₆ alkoxy); and

rings fused with said ring of 7 to 9 constituent members wherein saidfused rings include 0 to 3 rings each fused with said 7 to 9 memberedring and selected from benzene, cyclopropanone, and cyclopropane whereinthe fused benzene and cyclopropane rings are optionally furthersubstituted with from one to three substituents selected from the groupconsisting of C₁ to C₆ alkyl, halo (preferably from 0 to 2 halo selectedfrom chloro, bromo and fluoro and most preferably fluoro) and C₁ to C₆alkoxy;

and wherein at least one ring member selected from nitrogen and carbonis substituted by the further Q polymer unit.

In some embodiments, the polymer-bioactive agent conjugate comprises atleast one moiety of formula (IX):

wherein the ring “A” may be said ring of from 7 to 9 constitutent ringmembers.

Co-monomers useful for the preparation of polymer-bioactive conjugatesof the invention comprise terminal functional groups comprising analkyne and/or an azide. One skilled in the relevant art would understandthat under appropriate reaction conditions, an alkyne and an azidecontaining functional groups can covalently react to form a triazolemoiety. Click reaction conditions have been described in for example,Chem. Rev. 2008, 108, 2952, Angew Chem Int Ed 2001, 40, 2004, Angew ChemInt Ed Engl. 2002, Jul. 15, 41(14): 2596-9, Aldrichimica Acta 2010, 43(1) 15 and Accounts of Chemical Research 44 (9): 666-676

In accordance with one form of the invention, the triazole moietiesconstitute at least 10 mol % of the polymer backbone of thepolymer-bioactive agent conjugates. In some embodiments, the triazolemoieties constitute at least 20 mol % of the polymer backbone.

A polymer-bioactive agent conjugate according to one aspect of theinvention comprises a bioactive agent selected from prostaglandinanalogues. The prostaglandin analogue is preferably an analogue of thePGF2α class of prostaglandin. The prostaglandin analogue is conjugatedto the polymer backbone at the 1 position of the prostaglandin analogue.The prostaglandin analogue is conjugated to the polymer backbone via anester linking group.

In one set of embodiments, the bioactive agent D is a releasableprostaglandin analogue of formula Xb:

wherein:

represents the point of attachment of the prostaglandin analogue tolinking group Z;

represents a double or single bond;

Y is optionally substituted C₄ to C₁₀ hydrocarbyl or optionallysubstituted C₄ to C₁₀ hydrocarbyloxy;

R⁹ and R¹¹ are hydroxy; and

W is hydroxy and U is hydrogen, or W and U are both fluoro, or W and Utogether form oxo.

Some specific examples of releasable prostaglandin analogues of formulaedescribed herein are latanoprost, travoprost, bimatoprost andtafluprost, the free acid forms of latanoprost, travoprost (known asfluprostenol), bimatoprost and tafluprost, as well as carboprost,unoprostone and dinoprost.

In some embodiments, a polymer-bioactive agent conjugate according tothe invention is a copolymer of at least one monomer of formula (IV):

where:

-   -   X may be the same or different at each occurrence and represents        a terminal functional group comprising an alkyne or an azide;    -   Q is independently selected at each occurrence and may be        present or absent and when present, represents a linking group;    -   R is an optionally substituted linear or branched hydrocarbon        and may comprise optionally substituted aromatic hydrocarbon or        heteroaromatic hydrocarbon    -   Z is a cleavable linking group; and    -   D is a bioactive agent selected from prostaglandin analogues;        with at least one monomer of formula (V):

A-LA]_(n)  (V)

where:

A may be the same or different at each occurrence and represents a groupcomprising a terminal functional group comprising an alkyne or an azide,wherein said terminal functional group is complementary to the terminalfunctional group of X;

L is an optionally substituted linker group; and

n is an integer and is at least 1.

The moieties of formula (I), (II), (III) and (IX) can be produced whenmonomers of formula (IV) and formula (V) react under click chemistryconditions. Such moieties of formula (I), (II), (III) and (IX) thereforeform part of the structure of the backbone polymer chain.

In some embodiments, polymer-bioactive agent conjugates of the inventionare formed with a monomer of formula (V), where L is a linker groupcomprising a linker moiety selected from the group consisting ofoptionally substituted linear or branched aliphatic hydrocarbon,optionally substituted carbocyclyl, optionally substituted heterocyclyl,optionally substituted aryl, optionally substituted heteroaryl, and anoptionally substituted polymeric segment.

In some embodiments of a monomer of formula (V), L comprises abiodegradable polymer. Biodegradable polymers may include at least onebiodegradable moiety selected from the group consisting of an ester, anamide, a urethane, a urea and a disulfide moiety.

In some embodiments of a monomer of formula (V), L comprises a polymerselected from the group consisting of a polyether, a polyester, apolyamide, a polyurethane, and copolymers thereof.

In some embodiments of a monomer of formula (V), L comprises afunctional group selected from the group consisting of an amide, ether,ester, urethane, urea, and carbonate ester.

In some embodiments of a monomer of formula (V), n is 1, 2 or 3.

In some embodiments of a monomer of formula (IV), Q is present and saidQ comprises a functional group selected from the group consisting of anamide, ether, ester, urethane, urea, and carbonate ester functionalgroup.

In some embodiments of a monomer of formula (IV), Q is present and eachQ-X is independently selected from the following group:

In some embodiments of a monomer of formula (IV), each Q-X is a group offormula (VII):

where:

X is a terminal functional group selected from the group consisting ofan alkyne and an azide; and

m is an integer in the range of from 0 to 10, preferably in the range offrom 1 to 5.

In some embodiments of a monomer of formula (IV), R is an optionallysubstituted linear or branched hydrocarbon having from 1 to 12 carbonatoms.

In some embodiments, polymer-bioactive agent conjugates of the inventionare formed when at least one monomer of formula (IV) is reacted with amonomer for formula (V) such that the drug is pendant to atriazole-containing polymer backbone according to formula (I).

In one form of the invention, two or more monomers of formula (IV) arereacted with a monomer of formula (V). In such embodiments, the monomersof formula (IV) may contain different bioactive agents (D), such thatthe resulting polymer conjugate contains a mixture of differentbioactive agents. The different bioactive agents may, for example, be amixture of a prostaglandin analogue and a β-blocker.

In some embodiments, polymer-bioactive agent conjugates of the inventionare formed when a monomer of formula (IV) is reacted with acomplementary monomer of formula (IV) such that the bioactive agent ispendant to a triazole-containing polymer backbone according to formula(Ib).

In some embodiments, a polymer-bioactive agent conjugate according toany one of the embodiments described herein comprises at least about 15mol % bioactive agent.

Polymer-bioactive agent conjugates of the present invention may beincorporated into drug delivery systems, therapeutic devices, articlesor preparations, and pharmaceutical products for the treatment of ocularhypertension.

In another aspect, the present invention provides a pharmaceuticalproduct as an ocular implant or drug delivery system for the treatmentof glaucoma comprising a polymer-bioactive agent conjugate of any one ofthe embodiments described herein. The implant may be in the form of asolid article, deformable solid, hydrogel, or liquid for placement inthe eye of a subject.

In another aspect, there is provided a method for the treatment ofglaucoma in a subject suffering glaucoma in one or both eyes, the methodcomprising administering an article comprising a polymer-bioactive agentconjugate of any one of the embodiments described herein to an eyeafflicted with glaucoma. In one set of embodiments, the method comprisesdepositing the article in the lumen of a needle and injecting thearticle into the eye from the needle.

In another aspect, there is provided use of a polymer-bioactive agentconjugate of any one of the embodiments described herein the manufactureof a pharmaceutical product for the treatment of glaucoma. In one set ofembodiments, the pharmaceutical product is in the form of an ocularimplant. An ocular implant comprising the polymer-bioactive agentconjugate may be injectable.

BRIEF DESCRIPTION OF THE DRAWINGS

Examples of the invention are described with reference to the attacheddrawings.

In the drawings:

FIG. 1 is a graph showing the cumulative release of latanoprost freeacid from the polymers of Example 58 and Example 59 in isotonicphosphate buffer pH 7.4.

FIG. 2 is a graph showing the cumulative release of latanoprost freeacid from the polymers of Example 58, Example 55, Example 64, Example 65and Example 66 in isotonic phosphate buffer pH 7.4.

FIG. 3 is a graph showing the cumulative release of latanoprost freeacid from the polymers of Example 68 and Example 74 in isotonicphosphate buffer pH 7.4.

FIG. 4 is a graph showing the cumulative release of latanoprost freeacid and timolol from the polymer of Example 73 in isotonic phosphatebuffer pH 7.4.

FIG. 5 is a graph showing the cumulative release of latanoprost freeacid from the polymers of Example 82, Example 83, Example 84 and Example85 in isotonic phosphate buffer pH 7.4.

DETAILED DESCRIPTION OF THE INVENTION

In one aspect, the present invention relates to a polymer-bioactiveagent conjugate comprising a polymer backbone and a plurality ofreleasable bioactive agents covalently bonded to and pendant from thepolymer backbone. In accordance with this aspect, the polymer backbonecomprises a plurality of triazole moieties. The releasable bioactiveagents are selected from the group consisting of prostaglandinanalogues, β-blockers, and mixtures thereof and comprise prostaglandinanalogues covalently bonded to and pendant from the polymer backbonefrom the 1-position of the prostaglandin analogue via an ester linkinggroup. Bioactive agents used in the polymer conjugate of the inventionmay also be referred to herein as “drugs” or “prodrugs”.

The term “drug” refers to a substance for therapeutic use whoseapplication (or one or more applications) involves: a chemicalinteraction, or physico-chemical interaction, with a subject'sphysiological system; or an action on an infectious agent, or on a toxinor other poison in a subject's body, or with biological material such ascells in vitro.

As used herein, the term “prodrug” refers to a derivative of the drugmoiety, wherein the derivative may have little or none of the activityof the drug moiety per se yet is capable of being converted in vivo orin vitro into a bioactive moiety. An example of such derivatisation isthe acetylation of one or more hydroxyl groups on a bioactive moiety,such that subsequent to being released in vivo the released prodrug isdeactylated to produce the drug moiety.

As used herein, the term “pharmaceutically acceptable salt” means thosesalts that are safe and effective for use in pharmaceuticalpreparations. Pharmaceutically acceptable salts include salts of acidicgroups present in compounds of the invention. Suitable salts may includesodium, potassium, ammonium, calcium, diethylamine and piperazine saltsand the like. Pharmaceutically acceptable salts are described in Stahl PH, Wermuth C G, editors. 2002. Handbook of pharmaceutical salts:Properties, selection and use. Weinheim/Zurich: Wiley-VCHNHCA.

Polymers having bioactive agents covalently attached thereto aresometimes referred to in the art as “polymer—bioactive agentconjugates”. In some instances, it may be convenient to refer to apolymer-bioactive agent conjugate of the invention as a“bioactive-polymer conjugate”, “polymer-drug conjugate”, “drug-polymerconjugate”, “polymer conjugate”, or simply a “conjugate”.

Polymer-bioactive agent conjugates of the invention comprise a polymerbackbone comprising a plurality of triazole moieties. Each triazolemoiety is incorporated in the structure of the polymer chain, and formspart of the polymer backbone. Accordingly, the polymer backbone may beconsidered to be a polytriazole polymer.

The triazole moieties present in the polymer backbone are 1,2,3-triazolemoieties. A skilled person will understand that such triazole moietiesare products of an alkyne/azide reaction cycloaddition reactionperformed under “click” chemistry conditions.

As used herein, the expression forming “part of the polymer backbone”means that the triazole moiety is part of the string of atoms that areeach connected so as to form the polymer chain. In embodiments where thepolymer backbone has a branched structure (i.e. has one or more branchesor side chains extending from a main polymer chain), the triazole moietymay be part of a side chain as well as the main chain of the polymer.However, the expression is intended to exclude polymer structures wheretriazole moieties are present only in the side chain.

Polymer-bioactive agent conjugates of the invention, which have aplurality of triazole moieties in its polymer backbone, can be preparedthrough the use of click chemistry. The term ‘click chemistry’ wascoined by Professor K. Barry Sharpless in 2001 to describe a series ofchemical reactions defined by their modular nature, high yield,stability of products in vivo, stereospecificity, high atom economy andhigh thermodynamic driving force. A number of ‘click’ reactions exist,with several of them involving a cycloaddition reaction betweenappropriate functional groups to generate a stable cyclic structure.

Using click chemistry, at least two co-monomers of appropriatecomplementary terminal functionality can covalently react to form thepolymer-bioactive agent conjugate of the invention. At least one of theco-monomers carries a pendant bioactive agent. During polymerisation ofthe co-monomers to form the conjugate, the complementary terminalfunctional groups in the co-monomers react with one another and form atriazole moiety as a product of the covalent coupling. This results inthe co-monomers being linked together via the triazole moiety.Therefore, the resulting polymer-bioactive agent conjugate comprisestriazole moieties as a part of its polymer backbone structure.

As used herein, the terms “polymer” and “polymer backbone” encompassesall parts of the conjugate, with the exception of the bioactive agent,which in formulae shown herein below can be represented by the moietiesD, D¹ or D². Thus, the polymer backbone would encompass the linkinggroup Z, shown in formulae herein described, unless otherwise indicated.

Polymer-bioactive agent conjugates prepared with click chemistry have anumber of significant advantages over those prepared by other methods.One advantage of click reactions is that it can be used to provide asimpler method for preparing polymer-bioactive conjugates containingbioactive agents that have multiple reactive nucleophilic functionality.In the case of prostaglandin analogues and β-blockers, these bioactiveagents contain multiple nucleophilic functional groups. For instance,prostaglandin analogues can contain hydroxy and carboxy functionalgroups, while β-blockers contain hydroxy and amino functional groups. Itwould be appreciated that such nucleophilic functional groups mightotherwise need to be protected in order to avoid the possibility ofundesirable intra-chain incorporation of the bioactive agent duringpolymer synthesis. As the click reaction is almost completely orthogonalin terms of its reactivity to the reactivity exhibited by functionalgroups such as hydroxyl groups, amino groups and other nucleophiliccentres, protecting group strategies are not required as unprotectedreactive functional groups (such as hydroxyl groups and amino groups)present in a bioactive agent would take no part in any click reaction.

A further advantage of click reactions is that it can allow polymersynthesis to proceed under relatively mild conditions, for example, atlower temperatures than that used in a number of conventionalstep-growth polymerisation techniques.

1,2,3-Triazole moieties can be produced through the reaction ofco-monomers having appropriate complementary terminal functional groupscomprising alkyne and/or azide functionalities, under click reactionconditions. The terms “complementary terminal functionality” and“complementary terminal functional group” as used in the context of thepresent invention means a terminal chemical group that is capable ofreacting with another chemical group to form a covalent intermolecularbond there between.

An appropriate click reaction for the formation of 1,2,3-triazoles isthe Huisgen 1,3-dipolar cycloaddition of azides and alkynes (thermal)which gives a mixture of the 1,4 and 1,5 regioisomers of the1,2,3-triazole. Click reactions suitable for forming triazole moietiesmay also be metal catalysed. For example, a Copper(I)-catalyzedAzide-Alkyne Cycloaddition (CuAAC) variant of the Huisgen cycloadditionof azides and terminal alkynes forms 1,2,3-triazoles. Use of a coppercatalyst in the Huisgen cycloaddition reaction results in formation of a1,4-substituted 1,2,3-triazole from azides and terminal alkynes, whileuse of a ruthenium catalyst enables use of terminal or internal alkynesand results in the formation of the alternate 1,5-regiosiomer. The useof a silver catalyst also results in the 1,4-substituted 1,2,3-triazole.Other metals that can be used include, but are not limited to, Ni, Pt,Pd, Rh, and Ir; the regiochemistry of the 1,2,3 triazole resulting fromthe use of these metal catalysts is less well defined Some exemplaryclick functional groups have been described by W. H. Binder and R.Sachsenhofer in Macromol. Rapid Commun., 2007, 28, 15-54, the disclosureof which is incorporated herein by reference.

In addition to the thermal and metal catalysed variants of the Huisgencycloaddition of azides and alkynes, a more recent development centreson the development of a metal-free, strain promoted azide-alkynecycloaddition (SPAAC). In this variant, no catalyst is required as thealkyne is activated and made more reactive by incorporation of thealkyne functionality into a strained ring and/or by theselectiveplacement of electron withdrawing functionality and heteroatoms in thevicinity of the alkyne group. The regiochemistry of this SPAAC is mixedwith both 1,4 and 1,5 1,2,3 triazoles being formed.

The use of appropriately functionalised co-monomers to prepare thepolymer-bioactive agent conjugate can advantageously enable thecomposition, structure and molecular weight of the conjugate to becontrolled. In contrast, polymers prepared by step growth polymerisationmay have less reproducible molecular weights and a broader molecularweight distribution. Control over the structure and/or composition ofthe polymer-bioactive agent conjugate may be advantageous for regulatorypurposes.

In some embodiments, the polymer-bioactive conjugate comprises a moietyof formula (I):

where:

-   -   T at each occurrence represents a triazole moiety;    -   Q is independently selected at each occurrence and may be        present or absent and when present, represents a linking group;    -   R is an optionally substituted linear or branched hydrocarbon        and may comprise optionally substituted aromatic hydrocarbon and        or heteroaromatic hydrocarbon;    -   Z is a cleavable linking group; and    -   D is a releasable bioactive agent.

The polymer-bioactive agent conjugate typically comprises a plurality ofmoieties of formula (I), each group represented by Q, R, Z and D isindependently selected and may be the same or different in each moiety.

In formula (I), the bioactive agent (represented by D) compriseprostaglandin analogues. Examples of prostaglandin analogues aredescribed herein.

Polymer-bioactive conjugates comprising a plurality of moieties offormula (I) may have moieties of formula (I) adjacent to each other orspaced apart within the polymer conjugate.

An important feature of the polymer-bioactive conjugates of theinvention is that its polymer backbone comprises a plurality of triazolemoieties. The triazole moieties in formula (I) are represented by thegroup T. Thus, the moiety of formula (I), which carries a pendantbioactive agent, is coupled to the remainder of the polymer backbone viatriazole moieties.

In some embodiments, the polymer-bioactive agent conjugate comprises apolymer backbone comprising at least one triazole moiety selected fromthe group consisting of formula (II), (III) and (IX):

wherein in formula (IX), A represents an optionally substituted cyclicgroup, preferably said ring of from 7 to 9 constitutent ring members.

In some embodiments, a polymer-bioactive agent conjugate comprising atriazole moiety of formula (II) may comprise a moiety selected fromformula (IIa) and (IIb):

The moiety of formulae (II), (IIa) and (IIIb) comprises a1,4-substituted triazole moiety. Such a triazole moiety may be referredto herein as a 1,4-regioisomer.

In some embodiments, a polymer-bioactive agent conjugate comprising atriazole moiety of of formula (III) may comprise a moiety selected fromformula (IIIa) and (IIIb):

The moiety of formulae (III), (IIIa) and (IIIb) comprises a1,5-substituted triazole moiety. Such a triazole moiety may be referredto herein as a 1,5-regioisomer.

In some embodiments, a polymer-bioactive agent conjugate comprising amoiety of formula (IX) may comprise a moiety of formula (IXa) or (IXb):

In formulae (IXa) and (IXb), A represents an optionally substitutedcyclic group. Preferably the cyclic group comprises from 7 to 9 ringatoms. The ring atoms are each independently selected from the groupconsisting of C, N, O and S, preferably C, N and S. In one preference, Ais C8 cycloalkyl. In one set of embodiments the ring “A” is said ring offrom 7 to 9 constitutent ring members described above.

In one set of embodiments of formulae (IXa) and (IXb), A is substitutedwith one or more substituents selected from the group consisting ofhydroxy (—OH), —Oalkyl, alkyl, halo (preferably fluoro), cycloalkyl,heterocycloalkyl, aryl and heteroaryl. Cycloalkyl, heterocycloalkyl,aryl and heteroaryl substituent groups may comprise from 3 to 6 ringatoms and may be fused to A. The optional substitutents may be locatedon any ring atom of the cyclic group.

In the moieties of formula (IIa), (IIb), (IIIa), (IIIb), (IXa) and(IXb):

-   -   Q may be present or absent and when present represents a linking        group;    -   R is an optionally substituted linear or branched hydrocarbon        and may comprise optionally substituted aryl or heteroaryl    -   Z is a cleavable linking group; and    -   D is a releasable bioactive agent selected from the group        consisting of prostaglandin analogues, β-blockers, and mixtures        thereof.

A further discussion of the groups Q, R, Z and D is provided below.

The polymer-bioactive agent conjugates of the invention may comprise aplurality of triazole moieties of formula (II), (III) or (IX) as hereindescribed. The triazole moieties may be independently selected at eachoccurrence.

The triazole moieties present in the polymer backbone may each of thesame type, or they may be a mixture of different types. For example, thetriazole moieties present in the polymer conjugates may each be the sameand be selected from formulae (IIa), (IIb), (IIIa), (IIIb), (IXa) or(IXb). Alternatively, the polymer backbone of the polymer conjugate maycomprise a mixture of these types of triazole moieties.

One skilled in the relevant art would understand that depending on themonomers employed in the synthesis of the polymer-bioactive conjugateand the reaction conditions, the resulting conjugate may comprise asingle type of triazole moiety selected from those of formulae (IIa),(IIb), (IIIa), (IIIb), (IXa) or (IXb), or it may comprise a combinationof such moieties.

In some embodiments, the conjugate may comprise a triazole moietyselected from those of formula (II) and (III), and preferably comprisesat least one moiety selected from formulae (IIa), (IIb), (IIIa) and(IIIb). Thus the triazole moieties present in the polymer backbone ofthe conjugates may each be 1,4-substituted triazole moieties,1,5-substituted triazole moieties, or a combination of theseregioisomers.

In accordance with one embodiment of the polymer-bioactive agentconjugates of the invention, the triazole moieties may constitute atleast 10 mol % of the polymer backbone. In some embodiments, thetriazole moieties may constitute at least 20 mol % of the polymerbackbone. In some embodiments, the triazole moieties may constitute atleast 30 mol % of the polymer backbone.

As each triazole moiety is a reaction product from the covalent couplingof co-monomers, the proportion of triazole moieties in the polymerbackbone may provide an indication of the degree of monomerincorporation in the polymer-bioactive agent conjugate.

The mol % of triazole moieties is determined on the basis of theproportion (on a molar basis) of such moieties within the polymerbackbone in the conjugate.

As an example, the proportion of triazole moieties in polymer conjugatesof the invention where a pendant bioactive moiety is coupled to thepolymer backbone via a cleavable linking group (represented by Z informulae described herein) may be determined by following equation:

${\% \mspace{14mu} {triazole}} = {\left( \frac{67.05}{\begin{bmatrix}{{MW}_{({{monomer}\text{-}{bioactive}\mspace{14mu} {agent}\mspace{14mu} {conjugate}})} +} \\{MW}_{({{co}\text{-}{monomer}})}\end{bmatrix} - {MW}_{({{bioactive}\mspace{14mu} {agent}\text{-}1})} + 17} \right) \times 100\%}$

The polymer backbone of the conjugates of the present invention have amolecular weight of about 250 Daltons to about 10 MM Daltons, preferablyfrom 500 Daltons to 2 M Daltons.

The conjugates of the invention comprise a plurality of releasablebioactive agents covalently bonded to and pendant from the polymerbackbone.

In some embodiments, conjugates of the invention comprise at least about5 mol %, at least 10 mol %, at least 15 mol %, at least 20 mol %, or atleast 30 mol % bioactive agent. The mol % of bioactive agent may bedetermined relative to the total number of moles of monomer that formthe polymer conjugate.

The conjugates of the present invention can accommodate high bioactiveagent loadings, minimising the amount of material required to deliver adose of bioactive agent. Bioactive agent loadings of at least 5% byweight, at least 10% by weight, at least 15% by weight, at least 20% byweight, or at least 30% by weight, relative to the total weight of thepolymer conjugate may be achieved.

In some embodiments, conjugates of the invention comprise up to 60 mol%, up to 70 mol %, up to 80 mol %, up to 90 mol % and even up to 100 mol% of conjugated bioactive agent, relative to the total number of molesof monomer that form the polymer conjugate. Those skilled in the artwould appreciate that the mol % of bioactive agent may be dependent onthe relative molar ratio of monomers used to form the polymer conjugate.

In some embodiments, polymer-bioactive agent conjugates of the inventioncomprise a moiety of formula (Ib):

where:

-   -   T at each occurrence represents a triazole moiety;    -   Q is independently selected at each occurrence may be present or        absent and when present represents a linking group;    -   R is an optionally substituted linear or branched hydrocarbon        and may comprise optionally substituted aromatic hydrocarbon or        heteroaromatic hydrocarbon;    -   Z¹ and Z² are each cleavable linking groups that may be the same        or different; and    -   D¹ and D² are each bioactive agents that may be the same or        different.

A moiety of formula (Ib) may occur when two moieties of formula (I) arecovalently coupled together in the polymer conjugate.

In the moiety of formula (Ib), each T may be independently selected froma triazole moiety of formula (II), (III) or (IX). For instance, each Tmay be independently selected from triazole moiety of formula (IIa),(IIb), (IIIa), (IIIb), (IXa) and (IXb).

In one set of embodiments, in the moiety of formula (Ib), each T may bea 1,4-substituted triazole moiety or a 1,5-substituted triazole moiety.Alternatively, formula (Ib) may comprise a combination of such 1,4 and1,5-regioisomers.

In the moiety of formula (Ib), each Q and R may be independentlyselected from any one of the moieties described herein for such groups.

The groups Z¹ and Z² in the moiety formula (Ib) are each cleavablelinking groups, which may be the same or different at each occurrence.Z¹ and Z² may each be independently selected from any one of the groupsdescribed herein for the group Z. Where Z¹ and Z² are different, thereexists the possibility that release of the bioactive agent can befurther controlled.

The bioactive agents D¹ and D² are coupled to Z¹ and Z² respectively viaa cleavable covalent bond. Examples of cleavable covalent bonds aredescribed herein with reference to the linking group Z.

The groups D¹ and D² in the moiety of formula (Ib) are each bioactiveagents, which may be the same or different at each occurrence. D¹ and D²may each be independently selected from any one of the bioactive agentsas described herein for the group D. In accordance with the invention,D¹ and D² may each be independently selected from the group consistingof prostaglandin analogues and β-blockers and comprise prostaglandinanalogues covalently bonded to and pendant from the polymer backbonefrom the 1-position of the prostaglandin analogue via an ester linkinggroup.

In some embodiments, it may be desirable for D¹ and D² to be same. Insuch embodiments, the bioactive agents are therefore of a single type ofdrug (i.e. the same prostaglandin analogue).

In some embodiments, it may be desirable for D¹ and D² to belong to thesame class of drug, but be different bioactive agents within the samedrug class. In such embodiments, the D¹ and D² may each be prostaglandinanalogues but be selected from different drugs within the class.

In some embodiments, it may be desirable for D¹ and D² to be different(e.g. a mixture of prostaglandin analogues and β-blockers). This mayenable different therapeutic agents to be delivered to a subject by asingle polymer conjugate. Without wishing to be limited by theory, it isbelieved that the use of a mixture of bioactive agents mayadvantageously provide an enhanced therapeutic effect (e.g. an additiveor synergistic effect) in lowering intraocular pressure. Combination eyedrops comprising a prostaglandin analogue in combination with aβ-blocker have been shown to provide a greater reduction of ocularhypertension than either of the single agent eye drops (Higginbotham etal., Arch Ophthalmol 2002:120, 915-922; Pfieffer et al. IOVS 2000:41(4),s754; Sjoquist et al. IOVS 2000:41(4), s572; Larsson et al. IOVS2000:41(4), s280; Martinez & Sanchez Eye 2009:23, 810-818;PCT/SE2001/002499). Thus a mixture of different bioactive agents in thepolymer conjugate may be more efficacious than a single type ofbioactive agent alone.

A polymer-bioactive agent conjugate comprising a moiety of formula (Ib)may have a higher loading of bioactive agent. For example, apolymer-bioactive agent conjugate comprising formula (Ib) may comprisemore than 50 mol % of bioactive agent. In some embodiments, thepolymer-bioactive agent conjugate may comprise up to 60 mol %, up to 70mol %, up to 80 mol % up to 90 mol % and even up to 100 mol % ofconjugated bioactive agent, relative to the total number of moles ofmonomer that form the polymer conjugate.

The “bioactive agent” (also represented as “D” in certain formulaeherein) employed in the polymer-bioactive agent conjugate of thecomprise prostaglandin analogues and mixtures thereof. Prostaglandinanalogues are intraocular pressure lowering drugs.

Ophthalmic pharmaceuticals such as prostaglandin analogues andβ-blockers are used to treat glaucoma and ocular hypertension. Thesedrugs are used as therapeutic agents to treat or alleviate increasedocular pressure associated with eye disorders such as glaucoma by actingto reduce intraocular pressure. As discussed above, prostaglandinanalogues exert an ocular hypotensive effect by increasing uveoscleraloutflow of aqueous humour while β-blockers lower intraocular pressure byreducing the production of aqueous humour in the eye.

Prostaglandin analogues bound to the polymer backbone of the conjugateof the invention are in pendant form. By being “pendant”, the bioactiveagents do not form part of the polymer backbone structure and as such,can be released without causing a reduction in the chain length of thepolymer backbone. The pendant configuration can also ensure efficientrelease of the drug.

A skilled person would appreciate that bioactive agents such asprostaglandin analogues and β-blockers possess functional groups.Functional groups in a bioactive agent may be used to promote covalentcoupling of the agent to the polymer backbone.

In the case of prostaglandin analogues, these bioactive agents comprisecarboxylic acid, hydroxy and amino (primary amino) functional groups.More specifically, prostaglandin analogues comprise carboxylic acid andhydroxy functional groups.

As discussed above, when a bioactive agent contains more than one suchfunctional group, there is a potential for these functional groups toreact with terminal functional groups in many monomers used in stepgrowth polymerisation. For example, polyurethane conjugates may beformed with a diisocyanate monomer and a diol monomer. The isocyanateand hydroxyl groups in the co-monomers react to form a urethane linkedpolymer. The diol monomer may include a conjugated bioactive agent. Insuch instances, if the conjugated bioactive agent also comprises a freehydroxyl functional group, the free hydroxyl group on the bioactiveagent may compete with the diol hydroxyl groups for reaction with anisocyanate group of the diisocyanate monomer. If this occurs, thebioactive agent may become incorporated in the polymer backbone of theconjugate, rather than being pendant.

As polymer-bioactive agent conjugates of the invention are preparedusing click chemistry, it is an advantage of the invention thatbioactive agents having multiple functional groups can be covalentlycoupled to the polymer backbone without the need to employ protectinggroup strategies, which might otherwise be used to protect certainfunctional groups from reaction to thereby ensure that a bioactive agentis covalently coupled to the polymer backbone in a preselected fashion.

In one aspect, a polymer-bioactive agent conjugate according to theinvention comprises a releasable bioactive agent selected fromprostaglandin analogues.

A “prostaglandin” is an endogenous substance typically derived from C20prostanoic acid illustrated below:

As used herein, the term “prostaglandin analogue” refers to a moleculethat is designed to bind to a prostaglandin receptor. Prostaglandinanalogues may be modified derivatives of endogenous prostaglandins orsynthetic analogues of endogenous prostaglandins. Prostaglandinanalogues can be in the form of a therapeutically active drug or aprodrug. Many prostaglandin analogues are prodrugs (for example, anester derivative of a prostaglandin). However, such prostaglandinprodrugs are often referred to as prostaglandin analogues as they act onthe prostaglandin F receptor, after the ester group is hydrolyzed toform a 1-carboxylic acid (free acid form of the drug).

The prostaglandin analogue, or a pharmaceutically acceptable saltthereof, is conjugated to the polymer backbone. The present inventionenables the prostaglandin analogue, or pharmaceutically acceptable saltthereof to be delivered to a desired site in order to produce atherapeutic effect.

In one embodiment, the bioactive agent is an analogue of a prostaglandinbelonging to the PGF2α class of prostaglandin. PGF2α prostaglandinanalogues are designed to bind to the prostaglandin F2α receptor.

Prostaglandin analogues as described herein constitute an α-chain, anω-chain and a 5-membered ring, numbered according to the C20 prostanoicacid as follows:

In one aspect, the present invention relates to a polymer-drug conjugatecomprising a polymer backbone and a PGF2α class of prostaglandinanalogue conjugated to the polymer backbone.

Prostaglandins analogues delivered by polymer-bioactive agent conjugatesof the invention comprise at least one functional group selected fromthe group consisting of a carboxylic acid group at the 1 position, ahydroxy group at the 9 position, a hydroxy group at the 11 position, anda hydroxy group at the 15 position.

The carboxylic acid group at the 1 position, and the hydroxy groups atthe 9, 11 and 15 position of the prostaglandin analogue can serve asreactive functional groups for conjugation of the prostaglandin drug toa polymer. In conjugating the drug to the polymer backbone, theprostaglandin analogue may be conjugated to the polymer backbone via aselected group at the 1, 9, 11 or 15 position. The drug moiety (denotedD in formulae described herein) linked to the polymer would therefore anacid residue (in the case of conjugation at the 1 position) or analcohol residue (in the case of conjugation at the 9, 11 or 15positions) of the ester, anhydride or carbonate linking groupconjugating the prostaglandin analogue to the polymer backbone. Themoiety represented by D may therefore be a releasable prostaglandinanalogue.

The prostaglandin analogue may be conjugated to the polymer backbone viaan ester, anhydride or carbonate linking group. Ester, linking groupshave been found to be hydrolytically labile in biological environmentsand can help to ensure that a sufficient amount of the drug iseffectively released from the polymer conjugate to achieve therapeuticlevels in the immediate vicinity of the polymer conjugate material.

When the prostaglandin analogue is conjugated to the polymer backbone byan ester linking group, the ester linking group may link the drug at aposition selected from the group consisting of the 1, 9, 11 and 15position of the drug.

When the prostaglandin analogue is conjugated to the polymer backbone bya carbonate linking group, the carbonate linking group may link the drugat a position selected from the group consisting of the 9, 11 and 15position of the drug.

When the prostaglandin analogue is conjugated to the polymer backbone byan anhydride linking group, the anhydride linking group may link thedrug at the 1 position of the drug.

As used herein, the term “acid residue” is a reference to that part ofan ester or anhydride linking group that is derived from a carboxylicacid functional group of a bioactive agent, after conjugation of thebioactive agent to the polymer backbone. The acid residue will generallyhave the structure —C(O)O—. In the case of a prostaglandin analogue, thecarboxylic acid group is located at the 1 position.

As used herein the term “alcohol residue” is a reference to that part ofan ester or carbonate linking group that is derived from a hydroxyfunctional group of a bioactive agent, after conjugation of thebioactive agent to the polymer backbone. The alcohol residue willgenerally have the structure —O—. In the case of a prostaglandinanalogue, the hydroxy group may be selected by located at the 9, 11 or15 position. In the case of a β-blocker, the hydroxy group is part ofthe beta-amino alcohol group of the drug molecule.

In one set of embodiments, the bioactive agent (D) is a prostaglandinanalogue of formula (X):

where:

represents a double or single bond;

W and U are selected from the group consisting of where W and U togetherform oxo (═O), where W and U are each halo, and where W is R¹⁵ and U ishydrogen;

R^(y) is an optional substituent selected from the group consisting ofoxo and hydroxy;

Y is optionally substituted C4 to C10 hydrocarbyl or optionallysubstituted C₄ to C₁₀ hydrocarbyloxy; and

one of R¹, R⁹, R¹¹ and R¹⁵ is linked to the polymer backbone andwherein:

R⁹, R¹¹ and R¹⁵ when linked to the polymer backbone are the alcoholresidue of an ester or carbonate linking group and R¹ when linked to thepolymer backbone forms the acid residue of an ester or anhydride linkinggroup; and

R¹ when not linked to the backbone is selected from the group consistingof —OH, —O(C₁₋₆ alkyl), and —NR^(a)R^(b) where R^(a) and R^(b) are eachindependently selected from the group consisting of H and C₁₋₆ alkyl;

R⁹ and R¹¹ when not linked to the polymer backbone are both hydroxy andwhere one of R⁹ and R¹¹ is linked to the backbone, the other is hydroxy;and

when R¹⁵ is not linked to the backbone then W is hydroxy and U ishydrogen, or W and U are each fluoro, or W and U together form oxo.

In some embodiments, the prostaglandin analogue is of formula (Xb):

wherein

represents the point of attachment of the prostaglandin analogue to Z;

represents a double or single bond;

Y is optionally substituted C₄ to C₁₀ hydrocarbyl or optionallysubstituted C4 to C10 hydrocarbyloxy;

R⁹ and R¹¹ are hydroxy;

W is hydroxy and U is hydrogen, or W and U are both fluoro, or W and Utogether form oxo.

In prostaglandin analogues of formula (Xb), Y is optionally substitutedC₄ to C₁₀ hydrocarbyl or optionally substituted C₄ to C₁₀hydrocarbyloxy. The hydrocarbyl (including the hydrocarbyl portion ofthe hydrocarbyloxy) may comprise aliphatic, alicyclic or aromatichydrocarbon groups or combinations thereof.

In some embodiments of formula (Xb), Y is optionally substituted withone or more substituents selected from halo and halo-C₁ to C₄ alkyl.Suitable halo may be fluoro, chloro, bromo or iodo. Preferred halo isfluoro. Halo-C₁ to C₄ alkyl may be perhalomethyl, such as for example,trifluoromethyl.

In some embodiments, Y is selected from the group consisting of C₄ toC₁₀ alkyl, C₄ to C₁₀ alkoxy, phenyl, phenyl substituted C₁ to C₄ alkyl,and phenyl substituted C₁ to C₄ alkoxy, wherein the groups areoptionally substituted with one or more groups selected from halo andperhalomethyl. In some specific embodiments, Y is selected from thegroup consisting of —(CH₂)₃CH₃, —OC₆H₄(meta-CF₃), —(CH₂)₅CH₃, —O(C₆H₅)and —CH₂(C₆H₅).

In formula (Xb), W and U represent substituent groups present on theprostaglandin analogue. In some embodiments, W and U together form anoxo (═O) substituent group. In other embodiments, W and U are each halosubstituent groups. Suitable halo may be fluoro, chloro, bromo or iodo.Preferred halo is fluoro. In other embodiments, W is R¹⁵ and U ishydrogen.

In accordance with the invention, the prostaglandin analogue is linkedto the polymer backbone by R¹. R¹ forms the acid residue (—C(O)—) of anester. In formulae described herein, the ester, linking group is formedwhen the prostaglandin analogue (represented by D) is conjugated withthe linking group Z. That is, the prostaglandin analogue of formula (X),together with Z, forms an ester linking group. Some specific examples ofZ are described below.

R¹ is linked to the polymer backbone via an ester linkage. In suchembodiments, R⁹, R¹¹ and R¹⁵ are not linked to the polymer backbone.

R⁹ and R¹¹ are each hydroxy groups.

In one set of embodiments, the bioactive agent is a prostaglandinanalogue of formula (Xe):

where:

represents a double or single bond;

W and U are selected from the group consisting of where W and U togetherform oxo (═O), where W and U are each halo, and where W is R¹⁵ and U ishydrogen;

R^(y) is an optional substituent selected from the group consisting ofoxo and hydroxy;

Y is optionally substituted C₄ to C₁₀ hydrocarbyl or optionallysubstituted C₄ to C₁₀ hydrocarbyloxy; and

R¹ is linked to the polymer backbone and wherein:

R¹ when linked to the polymer backbone forms the acid residue of anester linking group; and

R⁹ and R¹¹ are both hydroxy and

W is hydroxy and U is hydrogen, or W and U are each fluoro, or W and Utogether form oxo.

In some embodiments, the prostaglandin analogue is:

wherein:

represents the point of attachment of the prostaglandin analogue tolinking group Z;

represents a double or single bond;

Y is optionally substituted C₄ to C₁₀ hydrocarbyl or optionallysubstituted C₄ to C₁₀ hydrocarbyloxy;

R⁹ and R¹¹ are hydroxy;

W is hydroxy and U is hydrogen, or W and U are both fluoro, or W and Utogether form oxo.

A skilled person would be able to ascertain the chemical structure of avariety of prostaglandin analogues. Prostaglandin analogues conjugatedto polymer-drug conjugates of the invention may be in free acid form(including pharmaceutically acceptable salts thereof) or prodrug form.

By “free acid” form is meant that prostaglandin analogues as describedherein may present as a “free” carboxylic acid (i.e. COOH) or beconjugated to the polymer backbone through that free carboxylic acidgroup at the 1 position of the prostaglandin analogue. The freecarboxylic acid group is generally in the α-chain of the prostaglandinanalogue. In such cases, the prostaglandin analogue is releasable, orcan be released, in its free acid form. The free acid form mayoptionally be associated with a pharmaceutically acceptable salt.

In the context of the present invention it may be convenient to refer tothe prostaglandin analogues of general formula (X) as the free acid formof other prostaglandins. For example the free acid form of latanoprostis((Z)-7-[(1R,2R,3R,5S)-3,5-dihydroxy-2-[(3R)3-hydroxy-5-phenylpentyl]-cyclopentyl]hept-5-enoicacid.

Some examples of prostaglandin analogues that may be delivered by thepolymer-bioactive agent conjugates are latanoprost, travoprost,bimatoprost and tafluprost, the free acid form of latanoprost,travoprost (known as fluprostenol), bimatoprost and tafluprost, as wellas carboprost, unoprostone and dinoprost. These prostaglandin analoguesare shown in Table 1. Such drugs (either in prodrug or free acid form)are conjugated to the polymer backbone of the polymer conjugates of theinvention by one of the functional groups located at the 1, 9, 11 or 15positions of the prostaglandin analogue, and may be delivered orreleased in free acid or prodrug form. Preferably, the prostaglandinanalogue is selected from latanoprost and the free acid form oflatanoprost.

TABLE 1 Pro-drug form Free-acid form

In some embodiments of the present invention, D as shown in formulaedescribed herein is selected from the following group:

Drug 1-COOH PGF_(2α)

Carboprost

Latanoprost

Bimatoprost

Travoprost

Tafluprost

Unoprostone

In another aspect, a polymer-bioactive agent conjugate according to theinvention comprises a bioactive agent selected from β-blockers. Aβ-blocker is a drug that has pharmacological activity to block orantagonise β-adrenergic receptors. The β-blockers employed in thepolymer conjugates of the invention are preferably beta-amino alcoholβ-adrenergic antagonists.

Beta-amino alcohol β-adrenergic antagonists comprise an alcohol (—OH)and an amino (—NH₂, —NHR or —NR₂) functional group. The β-blocker isconjugated to the polymer backbone via an ester or carbonate linkinggroup formed with the alcohol moiety of the β-amino alcohol group.

In one set of embodiments the bioactive agent (D) is a β-blocker offormula (XX):

wherein:

E is a bond or —OCH₂— (preferably —OCH₂—);

R² is linked to the polymer backbone and is the alcohol residue of anester or carbonate linking group;

R³ and R⁴ are each independently selected from the group consisting ofH, and linear or branched C₁-C₄ alkyl optionally substituted by one ormore substituents selected from the group consisting of hydroxy,optionally substituted alkoxy, optionally substituted aryloxy,optionally substituted amido, optionally substituted cycloalkyl, andoptionally substituted aryl; (preferably R³ is H and R⁴ is isopropyl ortert-butyl); and

R⁵ is an optionally substituted cycloalkyl or aryl moiety (includingpolycyclic moieties).

In one embodiment the group R⁵ may be a group of formula

providing a bioactive agent (D) which is a β-blocker of formula (XXa):

wherein:

R² is linked to the polymer backbone and is the alcohol residue of anester or carbonate linking group;

represents a single bond or double bond;

E is a bond or —OCH₂—;

G at each occurrence is independently selected from the group consistingof carbon (C), nitrogen (N), oxygen (O) and sulphur (S), with theproviso that at least two G are carbon;

R³ and R⁴ are each independently selected from the group consisting ofH, and linear or branched C₁-C₄ alkyl optionally substituted by one ormore substituents selected from the group consisting of hydroxy,optionally substituted alkoxy, optionally substituted aryloxy,optionally substituted amido, optionally substituted cycloalkyl, andoptionally substituted aryl (preferably R³ is H and R⁴ is isopropyl ortert-butyl);

R^(c) at each occurrence is an optional substituent, or two R^(c) canjoin together to form an optionally substituted cycloalkyl or aryl ring;and

n is 0 or 1.

In one set of embodiments of formula (XX), R⁵ may be selected from thegroup consisting of 4-morpholin-4-yl-1,2,5-thiadiazol-3-yl,[2-(cyclopropylmethoxy)ethyl]-phenyl, 3,4-dihydronaphthalen-1(2H)-one,4-phenyl-acetamide, 1-napthyl, and 4-(2-methoxyethyl)phenyl.

In some embodiments, the bioactive agent (D) is β-blocker of formula(XXb):

wherein:

represents the point of attachment of the β-blocker to Z;

R³ and R⁴ are each independently selected from the group consisting ofH, and linear or branched C₁-C₄ alkyl optionally substituted by one ormore substituents selected from the group consisting of hydroxy,optionally substituted alkoxy, optionally substituted aryloxy,optionally substituted amido, optionally substituted cycloalkyl, andoptionally substituted aryl (preferably R³ is H and R⁴ is isopropyl ortert-butyl).

In some embodiments, the β-blocker is of formula (XXc):

wherein:

represents the point of attachment of the β-blocker to the ester orcarbonate linking group conjugating the drug to the polymer backbone;

R³ and R⁴ are each independently selected from the group consisting ofH, and linear or branched C₁-C₄ alkyl optionally substituted by one ormore substituents selected from the group consisting of hydroxy,optionally substituted alkoxy, optionally substituted aryloxy,optionally substituted amido, optionally substituted cycloalkyl, andoptionally substituted aryl (preferably R³ is H and R⁴ is isopropyl ortert-butyl).

Some specific examples of releasable β-blockers of formulae describedherein are betaxolol, carteolol, levobunolol, metripranolol, andtimolol, preferably timolol. These β-blockers are shown in Table 2. Theβ-blockers are conjugated to the polymer backbone of thepolymer-bioactive agent conjugate via the alcohol moiety of thebeta-amino alcohol group of the drug.

TABLE 2 Drug Structure betaxolol

levobunolol

timolol

carteolol

metripranolol

Although not necessarily depicted, those skilled in the art willappreciate that bioactive agents of general formulae described hereinmay have particular stereoisomeric structures and possibly, particulargeometric isomeric structures. For avoidance of any doubt, the generalformulae shown herein are intended to embrace all such structures.Stereoisomeric structures can include the (S)-enantiomer or the(R)-enantiomer of the bioactive agent, as well as racemic mixtures.

For example, the β-blocker timolol has (S) and (R) enantiomers of thefollowing structures:

When a bioactive agent can exist in different stereoisomers, thepolymer-bioactive agent conjugate may be enriched in one stereoisomer.In one set of embodiments, the polymer-bioactive agent conjugate maycomprise at least 70%, at least 80%, at least 90% or at least 95% of thedrug as one enantiomer.

In one set of embodiments, where the polymer-bioactive agent conjugatecomprises a β-blocker, it may comprise the (S)-enantiomer of theβ-blocker, such as for example, the (S)-enantiomer of timolol.

Polymer-bioactive agent conjugates of the invention comprise at leastone bioactive agent selected from the group consisting of prostaglandinanalogues and β-blockers conjugated to the polymer backbone. Moretypically, polymer conjugates of the invention comprise a plurality ofbioactive agents selected from prostaglandin analogues, and mixturesthereof.

In one set of embodiments, polymer-bioactive agent conjugates of theinvention comprise a moiety of formula (I):

where:

-   -   T at each occurrence represents a triazole moiety;    -   Q is independently selected at each occurrence and may be        present or absent and when present represents a linking group;    -   R is an optionally substituted linear or branched hydrocarbon        and may comprise optionally substituted aromatic hydrocarbon or        heteroaromatic hydrocarbon;    -   Z is a cleavable linking group; and    -   D is a releasable bioactive agent selected from a prostaglandin        analogue of formula (X).

Prostaglandin analogues bound to polymer conjugates of the invention arereleasable bioactive agents. The term “releasable” as used herein inconnection with bioactive agents mean that the bioactive agents arecapable of being covalently decoupled or cleaved from the polymerbackbone so as to be released into an environment in a biologicallyactive or physiologically active form. For example, the bioactive agentsare capable of being released or cleaved from the Z group defined ingeneral formulae (I), (Ib), (IIa), (IIb), (IIIa), (IIIb), (VIa) and(VIb) above. Release of the bioactive agents may be promoted by theconjugates being exposed to physiological conditions or a biologicalenvironment. Upon being released, the bioactive agent is bioactive orwill be converted in vivo or in vitro to a bioactive form (e.g. as inthe case of a prodrug bioactive agent).

The ability of the bioactive agents to be releasable will generally be aresult of the bioactive agents each being coupled to the polymerbackbone in pendant form via a cleavable linking group, which isrepresented by the moiety “Z” in formulae described herein. Thecleavable linking group may couple the bioactive agent to the polymerbackbone directly, or through a spacer moiety. Cleavage of the cleavablelinking group will therefore promote release of the bioactive agent.Some specific examples of Z are described below.

In one embodiment, the prostaglandin analogues are released such thatthey do not include a residue derived from the polymer backbone orlinking group Z. By this it is meant that each bioactive agent isreleased in their substantially original form (i.e. before beingconjugated) and are essentially free from, for example, fragments ofoligomer or polymer derived from the polymer backbone and/or group(s)linking the bioactive agent to the polymer backbone. Accordingly, inthis respect, the linking group Z in formulae described herein isconsidered to be a part of the polymer backbone of the conjugate.

In the moieties of formulae (I), (Ib), (IIa), (IIb), (IIa), (IIIb),(VIa) and (VIb), the bioactive agent (D) is coupled to R through acleavable linking group denoted by Z. As used herein “linking group”refers to a generally divalent substituent group that couples D to R.The substituent group is cleavable so that the bioactive agent isreleasable.

In some embodiments, the cleavable linking group represented by Z is acleavable covalent bond that directly couples the bioactive agent to thepolymer backbone.

In other embodiments, the cleavable linking group represented by Zcomprises a spacer moiety and a cleavable covalent bond. The spacermoiety is attached to the polymer backbone while the cleavable covalentbond couples the spacer moiety to the bioactive agent. In someembodiments of a polymer-bioactive conjugate of the invention, it is aproviso that Z does not include a triazole moiety. Thus, polymerconjugates of the invention do not include bioactive agents coupled tothe polymer backbone via a product of a click chemistry reaction.

The covalent bond coupling the bioactive agent (D) with the linkinggroup (Z) is not a carbon-carbon bond. Accordingly, the cleavablecovalent bond will generally form part of a functional group selectedfrom: esters; carbonates; and anhydrides. Of these functional groups,esters and carbonates are preferred. A skilled person would recognisethat such groups are capable of being cleaved, for examplehydrolytically, enzymatically, and/or by radical mechanisms, so as torelease the bioactive agent.

The present invention preferably employs a group selected from ester,anhydride and carbonate linking groups to conjugate the bioactive agentto the polymer backbone as such linking groups have been found to behydrolytically labile in biological environments. Such linking groupsmay also be generally more labile than other groups or moieties that maybe present in the polymer-bioactive agent conjugate, such as forexample, biodegradable moieties that may be present in the polymerbackbone of polymer conjugates of some embodiments of the invention.Ester, anhydride and carbonate linking groups may further help to ensurethat a sufficient amount of the drug is effectively released from thepolymer conjugate to achieve therapeutic levels in the immediatevicinity of the polymer conjugate material.

As discussed above, prostaglandin analogues delivered bypolymer-bioactive agent conjugates of the invention comprise at leastone functional group selected from the group consisting of a carboxylicacid group at the 1 position, a hydroxy group at the 9 position, ahydroxy group at the 11 position, and a hydroxy group at the 15position. When the bioactive agent is a prostaglandin analogue, thecleavable covalent bond forms part of an ester, carbonate or anhydride,depending on whether the drug is linked to the polymer backbone via the1, 9, 11 or 15 position.

The β-blockers delivered by polymer-bioactive agent conjugates of theinvention comprise a beta-amino alcohol group. When the bioactive agentis a β-blocker, the cleavable covalent bond forms part of an ester orcarbonate group as the bioactive agent is conjugated to the polymerbackbone via the alcohol (—OH) moiety of the beta-amino alcohol group.

When present, the prostaglandin analogues of formula (X) and theβ-blockers of formula (XX) as shown above are each coupled to thepolymer backbone by the group Z.

When the bioactive agent is a prostaglandin analogue of formula (Xb),the drug and Z form an ester or anhydride linking group. Accordingly, informula (Xb), the prostaglandin drug is covalently linked to Z so as toform part of an ester linkage or an anhydride linkage. In suchembodiments, the prostaglandin analogue will comprise the acid residueof the ester or anhydride linking group, while Z will comprise thealcohol residue of the ester or the acid residue of the anhydridelinking group. Upon hydrolysis or cleavage of the ester or anhydridelinking group, a carboxylic acid group will then form on theprostaglandin analogue, while an alcohol (—OH) group or carboxylic acid(—CO₂H) group will form on Z.

When the bioactive agent is a prostaglandin analogue of formula (Xa),(Xc) or (Xd), the bioactive agent and Z together form an ester orcarbonate linking group. In formulae (Xa), (Xc), (Xd), the prostaglandinanalogue is covalently linked to Z so as to form part of an esterlinkage or a carbonate linkage. In such embodiments, the bioactive agent(i.e. prostaglandin analogue) will comprise the alcohol residue of theester or carbonate linking group, while Z will comprise the acid residueof the ester or carbonate linking group. Upon hydrolysis or cleavage ofthe ester or carbonate linking group, an alcohol (—OH) group will thenform on the prostaglandin analogue, while a carboxylic acid (—CO₂H)group or a carbonic acid ester (—O(O)COH) group will form on Z. It willbe recognised by those skilled in the art that the carbonic acid residuewill spontaneously decompose to generate an alcohol residue of thelinking group and CO₂.

Breakdown of the cleavable covalent bond can be promoted hydrolytically(i.e. hydrolytic cleavage) and may take place in the presence of waterand an acid or a base. In some embodiments the cleavage may take placein the presence of one or more hydrolytic enzymes or other endogenousbiological compounds that catalyze or at least assist in the cleavageprocess. For example, an ester bond may be hydrolytically cleaved toproduce a carboxylic acid and an alcohol.

At the very least the bioactive agent will be releasable from theconjugate per se. However, as further described below, the polymerbackbone may also biodegrade in vivo or in vitro such that the polymerbackbone breaks into lower molecular weight fragments, with thebioactive agent remaining tethered to such a fragment(s) via Z. In thatcase, the bioactive agent will nevertheless still be capable of beingreleased or cleaved from Z, which may or may not still be associatedwith the polymer conjugate per se.

As indicated above, bioactive agents as described herein may be coupledto a spacer moiety, which in turn is attached to the polymer backbone.As used herein, the terms “spacer”, “spacer group” or “spacer moiety”refer to an atom or any straight chain or branched, symmetric orasymmetric compound capable of linking or coupling the bioactive agentto a polymer backbone.

In some embodiments, the “spacer”, “spacer group” or “spacer moiety”refers to a substituent which is generally divalent. As outlined above,the covalent bond between the spacer moiety and the bioactive agent iscleavable so that the bioactive agent is releasable.

Examples of suitable spacer moieties that may form part of Z include thedivalent form of a group selected from oxy (—O—), alkyl, alkenyl,alkynyl, aryl, acyl (including —C(O)—), carbocyclyl, heterocyclyl,heteroaryl, alkyloxy, alkenyloxy, alkynyloxy, aryloxy, acyloxy,carbocyclyloxy, heterocyclyloxy, heteroaryloxy, alkylthio, alkenylthio,alkynylthio, arylthio, acylthio, carbocyclylthio, heterocyclylthio,heteroarylthio, alkylalkenyl, alkylalkynyl, alkylaryl, alkylacyl,alkylcarbocyclyl, alkylheterocyclyl, alkylheteroaryl, alkyloxyalkyl,alkenyloxyalkyl, alkynyloxyalkyl, aryloxyalkyl, alkylacyloxy,alkyloxyacylalkyl, alkylcarbocyclyloxy, alkylheterocyclyloxy,alkylheteroaryloxy, alkylthioalkyl, alkenylthioalkyl, alkynylthioalkyl,arylthioalkyl, alkylacylthio, alkylcarbocyclylthio,alkylheterocyclylthio, alkylheteroarylthio, alkylalkenylalkyl,alkylalkynylalkyl, alkylarylalkyl, alkylacylalkyl, arylalkylaryl,arylalkenylaryl, arylalkynylaryl, arylacylaryl, arylacyl,arylcarbocyclyl, arylheterocyclyl, arylheteroaryl, alkenyloxyaryl,alkynyloxyaryl, aryloxyaryl, arylacyloxy, arylcarbocyclyloxy,arylheterocyclyloxy, arylheteroaryloxy, alkylthioaryl, alkenylthioaryl,alkynylthioaryl, arylthioaryl, arylacylthio, arylcarbocyclylthio,arylheterocyclylthio, and arylheteroarylthio, wherein where present theor each —CH₂— group in any alkyl chain may be replaced by a divalentgroup independently selected from —O—, —OP(O)₂—, —OP(O)₂O—, —S—, —S(O)—,—S(O)₂O—, —OS(O)₂O—, —N═N—, —OSi(OR^(a))₂O—, —Si(OR^(a))₂O—,—OB(OR^(a))O—, —B(OR^(a))O—, —NR^(a)—, —C(O)—, —C(O)O—, —OC(O)O—,—OC(O)NR^(a)— and —C(O)NR^(a)—, where the or each R^(a) may beindependently selected from hydrogen, alkyl, alkenyl, alkynyl, aryl,carbocyclyl, heteroaryl, heterocyclyl, arylalkyl, and acyl. The one ormore R^(a) groups may also be independently selected from hydrogen,C₁₋₁₈alkyl, C₁₋₁₈alkenyl, C₁₋₁₈alkynyl, C₆₋₁₈aryl, C₃₋₁₈carbocyclyl,C₃₋₁₈heteroaryl, C₃₋₁₈heterocyclyl, and C₇₋₁₈arylalkyl.

In some embodiments the spacer moiety may be branched. Where the spacermoiety is branched, two or more releasable bioactive agents may beappended to the spacer moiety.

In the lists above defining groups (generally divalent) from which eachspacer moiety may be selected, each alkyl, alkenyl, alkynyl, aryl,carbocyclyl, heteroaryl, and heterocyclyl moiety may be optionallysubstituted. For avoidance of any doubt, where a given spacer moietycontains two or more of such moieties (e.g. alkylaryl), each of suchmoieties may be optionally substituted with one, two, three or moreoptional substituents as herein defined.

In the lists above defining groups (generally divalent) from which theor each spacer moiety may be selected, where a given spacer moietycontains two or more subgroups (e.g. [group A][group B]), the order ofthe subgroups is not intended to be limited to the order in which theyare presented. Thus, a spacer moiety with two subgroups defined as[group A][group B] (e.g. alkylaryl) is intended to also be a referenceto a spacer moiety with two subgroups defined as [group B][group A](e.g. arylalkyl).

Some specific examples of spacer moieties that may form part of Zinclude: —O—; —C(O)—; —OC(O)— and optionally substituted:—OC(O)—C₁₋₁₈alkylene-C(O)—; —C(O)O—C₁-C₁₈alkylene-C(O)—; —O—Ar—C(O)O—;—O—Ar—C(O)—NR^(a)—; —O—Ar—; —O—Ar—; —C(O)O—Ar—C(O)O—;—C(O)O—Ar—C(O)—NR^(a)—; —C(O)O—Ar—; —C(O)O—Ar—;—NR^(a)C(O)—C₁-C₁₈alkylene-C(O)—; —C(O)O—C₁-C₁₈alkylene-O—;—OC(O)O—C₁-C₁₈alkylene-O—; —O—C₁-C₁₈alkylene-O—;—O—C₁-C₁₈alkylene-NR^(a)—; —OC(O)—C₁-C₁₈alkylene-NR^(a)—;—C(O)—C₁-C₁₈alkylene-NR^(a)—; —OC(O)—C₁-C₁₈alkylene-O—;—C(O)—C₁-C₁₈alkylene-O—; and —C(O)NR^(a)—C₁-C₁₈alkylene-NR^(a)— whereR^(a) is as defined above.

In one form of the invention, exemplary spacer moieties include: —O—;—C(O)—; —OC(O)O—C₁₋₁₈alkylene-O—; and —OC(O)—C₁₋₁₈alkylene-C(O)—, suchas —OC(O)—C₂₋₃alkylene-C(O)—, —O—C₅₋₆Ar—C(O)O and —C(O)O—C₅₋₆Ar—C(O)O—.

The choice of spacer moieties will determine the spacing of thebioactive agents from the polymer backbone. The skilled artisan would becapable of selecting the appropriate spacer moiety based on anevaluation of steric constraints, phase chemistry and surface chemistry.For example, larger bioactive agents can be advantageously spaced fromthe monomer by the choice of a longer spacer moiety.

In some embodiments of a polymer conjugate of the invention,

(a) the bioactive agent (D) is a prostaglandin analogue of formula (Xb),an ester linking group and Z is of a formula selected from the groupconsisting of:

(R) —O— (D);  (i)

(R) -J-Ar-O— (D);  (ii)

(R) -J-C₁-C₁₂alkylene-O— (D);  (iii)

(R) -J-Ar-J-C₁-C₁₂alkylene-O— (D);  (iv)

(R) -J-C₁-C₁₂alkylene-J-Ar—O— (D);  (v)

(R) -J-C₁-C₁₂alkylene-J-Ar-Q-C₁-C₁₂alkylene-O— (D);  (vi)

(R) —OC(O)— (D);  (vii)

(R) -J-Ar—OC(O)— (D); and  (Viii)

(R) -J-C₁-C₁₂alkylene-OC(O)— (D);  (ix)

wherein:(R) indicates the end of the linking group bonded to the R group in thepolymer backbone and (D) indicates the end of the linking group bondedto the prostaglandin drug;Ar is optionally substituted aromatic or heteroaromatic hydrocarbon; andJ is selected from the group consisting of —O—, —C(O)—, —O—C(O)—,—OC(O)—O—, —C(O)—O—, —C(O)OC(O)—, —C(O)NR^(a)C(O)—, —OC(O)NR^(a)—,—NR^(a)C(O)O—, —NR^(a)—, —NR^(a)C(O)NR^(a)—, —NR^(a)C(O)—, —C(O)NR^(a)—,—S—, —O—C(S)—, —C(S)—O—, —S—C(O)—, —C(O)—S—, —NR^(a)C(S)—, and—C(S)NR^(a)—, where R^(a) is hydrogen or C₁ to C₆ alkyl.

The terms “aromatic hydrocarbon” and “heteroaromatic hydrocarbon”,including indefinition of R and Z (in connection with the group “Ar”)denotes any ring system comprising at least one aromatic orheteroaromatic ring. The aromatic hydrocarbon or heteroaromatichydrocarbon may be optionally substituted by one or more optionalsubstituents as described herein.

The aromatic hydrocarbon or heteroaromatic hydrocarbon may comprise asuitable number of ring members. In some embodiments, the aromatichydrocarbon or heteroaromatic hydrocarbon comprises from 5 to 12 ringmembers. The term “ring members” denotes the atoms forming part of thering system. In an aryl group, the ring atoms are each carbon. In aheteroaromatic hydrocarbon group one or more of the rings atoms areheteroatoms. Examples of heteroatoms are O, N, S, P and Se, particularlyO, N and S. When two or more heteroatoms are present in a heteroaromatichydrocarbon group, the heteroatoms may be the same or different at eachoccurrence.

Suitable aromatic hydrocarbon may be selected from the group consistingof phenyl, biphenyl, naphthyl, tetrahydronaphthyl, idenyl, azulenyl, andthe like.

Suitable heteroaromatic hydrocarbon may be selected from the groupconsisting of furanyl, thiophenyl, 2H-pyrrolyl, pyrrolinyl, oxazolinyl,thiazolinyl, indolinyl, imidazolidinyl, imidazolinyl, pyrazolyl,pyrazolinyl, isoxazolidinyl, isothiazolinyl, oxadiazolinyl, triazolinyl,thiadiazolinyl, tetrazolinyl, pyridinyl, pyridazinyl, pyrimidinyl,pyrazinyl, triazenyl, indolyl, isoindolinyl, benzimidazolyl,benzoxazolyl, quinolinyl, isoquinolinyl, and the like.

In some embodiments of the invention, Ar is an optionally substitutedC₅₋₁₂ aromatic hydrocarbon. In some embodiments Ar is optionallysubstituted phenyl (C₆ aromatic hydrocarbon). In some specificembodiments, Ar is para or meta substituted phenyl. In some specificembodiments, Ar is optionally substituted pyridyl (C₅ heteroaromatic).

In some embodiments of a polymer-bioactive agent conjugate of theinvention, when the bioactive agent (D) is a prostaglandin of formula(Xb) linked to the polymer backbone, then Z is of a formula selectedfrom the group consisting of:

(R) —O— (D);

(R) —OC(O)—Ar—O— (D);

(R) —NHC(O)—Ar—O— (D);

(R) —C(O)O—C₁₋₁₂alkylene-O— (D);

(R) —OC(O)—C₁-C₁₂alkylene-O— (D).

(R) —OC(O)— (D);

(R) —OC(O)—Ar—OC(O)— (D);

(R) —NHC(O)—Ar—OC(O)— (D);

(R) —C(O)O—C₁-C₁₂alkylene-OC(O)— (D);

(R) —OC(O)—O—C₁-C₁₂alkylene-O— (D); and

(R) —OC(O)—C₁-C₁₂alkylene-OC(O)— (D).

In one embodiment, when the prostaglandin analogue (D) is linked via R1to the polymer backbone, then Z is —O—; —OC(O)—;—OC(O)—O—C₁-C₁₂alkylene-O—, —O—C₆-aryl-C(O)O—; —O—C₆-aryl-C(O)NH—;—O-Pyridoxine-; and —O— Phloroglucinol-.

In one embodiment, when the prostaglandin analogue (D) is linked via R¹to the polymer backbone, the linker group Z is of formula:

wherein R¹ is selected from the group consisting of hydrogen and C₁ toC₁₁ alkyl, preferably from the group consisting of hydrogen, methyl,ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, and tert-butyl.

In one embodiment, when the prostaglandin analogue (D) is linked viapolymer backbone, the linker group Z is of formula:

wherein R¹ is selected from the group consisting of hydrogen and C₁ toC₁₁ alkyl preferably from the group consisting of hydrogen, methyl,ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, and tert-butyl.

Conjugates of the invention may, in addition to moieties of formula (I)or (Ib), comprise a linker segment as a part of its polymer backbonestructure. The linker segment may be coupled to one or more moieties offormula (I) or (Ib). Each coupling to a moiety of formula (I) or (Ib)occurs via a triazole moiety. Thus, when present, the linker segment maybe used to space apart moieties of formula (I) or (Ib) in theconjugates.

As used herein, the term “linker segment” refers to a segment that isgenerally a divalent.

The presence of a linker segment can be advantageous, as it enables thephysical properties of the conjugates to be adjusted by selection of adesired linker segment, thus providing avenues for macromoleculestailored for use in particular applications. For example, hard segmentsand/or soft segments may be incorporated into the polymer backbone ofthe conjugates through the selection of an appropriate linker segment.

The linker segment may be introduced to the polymer backbone of thepolymer-bioactive agent conjugate by polymerising a monomer comprising apendant bioactive agent with a co-monomer comprising a linker moiety. Insuch embodiments the linker segment may be derived from the linkermoiety of the co-monomer.

In some embodiments, the linker segment may be selected from the groupconsisting of optionally substituted linear or branched aliphatichydrocarbon, optionally substituted carbocyclyl, optionally substitutedheterocyclyl, optionally substituted aryl, optionally substitutedheteroaryl, an optionally substituted polymeric linker segment, andcombinations thereof.

Optionally substituted linear or branched aliphatic hydrocarbon linkersegments may be selected from optionally substituted C₁ to C₂₀, C₁ toC₁₀ or C₁ to C₆ linear or branched aliphatic hydrocarbons. The aliphatichydrocarbons may be saturated or unsaturated hydrocarbon. Optionallysubstituted aliphatic hydrocarbon linker segments may be derived fromfatty acids (such as acetic acid, propionic acid, butyric acid, valericacid and caproic acid), sugar alcohols (such as xylitol and mannitol),and amino acids (such as glutamic acid and lysine).

Optionally substituted carbocyclyl linker segments may comprise from 3to 12, 3 to 8 or 5 to 6 carbon ring members.

Optionally substituted heterocyclyl linker segments may comprise from 3to 12, 3 to 8 or 5 to 6 ring members and 1, 2, 3, 4 or more heteroatomsas a part of the ring. The heterotoms may be independently selected fromthe group consisting of O, N and S.

Optionally substituted aryl linker segments may comprise from 3 to 12, 3to 8 or 5 to 6 carbon ring members and at least one unsaturation.

Optionally substituted heteroaryl linker segments may comprise from 3 to12, 3 to 8 or 5 to 6 ring members and 1, 2, 3, 4 or more heteroatoms asa part of the ring. The heterotoms may be independently selected fromthe group consisting of O, N and S. The heteroaryl linker segment alsocomprises at least one unsaturation.

Optionally substituted polymeric linker segments may comprise anysuitable polymer or copolymer. In some embodiments, it can be desirablefor the polymer to be biocompatible and/or biodegradable. One skilled inthe relevant art would be able to select suitable biocompatible and/orbiodegradable polymers. Exemplary biocompatible polymers may be selectedfrom polyethers, polyesters, polyamides, polyurethanes, and copolymersthereof. Copolymers may be for example, poly(ether-esters),poly(urethane-ethers), poly(urethane-esters), poly(ester-amides) and thelike. Preferred biocompatible polymers are polyethers, polyesters,polyurethanes, and copolymers thereof.

Exemplary polyethers may be polymers of C₂ to C₄ alkylene diols, such aspolyethylene glycol and polypropylene glycol, preferably polyethyleneglycol.

Exemplary polyesters may be polycaprolactone, poly(lactic acid),poly(glycolic acid) and poly(lactic-co-glycolic acid).

In one form, the polymeric linker segment may comprise a biodegradablepolymer. Suitable biodegradable polymers may comprise at least onebiodegradable moiety selected from the group consisting of an ester, anamide, a urethane (carbamate), a urea and a disulfide moiety, preferablyan ester or urethane moiety. Biodegradable polymers used in thepolymeric linker segment may have a combination of such moieties.

The linker segment may modify the properties of the conjugate andinfluence bioactive agent release. For example, a polyether linkersegment (e.g. polyethylene glycol) may make the conjugate morehydrophilic. Without wishing to be limited by theory, it is believedthat a conjugate comprising a hydrophilic segment as part of its polymerbackbone could promote release of the bioactive agent. This may beadvantageous where more rapid release of the bioactive agent is desired.Conversely, a conjugate comprising a hydrophobic segment as part of itsbackbone might delay release of the bioactive agent. A hydrophobicsegment could be introduced by incorporation of a hydrophobic polymericlinker (e.g. a polycarpolactone linking moiety) into the conjugate.

In one set of embodiments, the polymer-bioactive agent conjugatecomprises a polyether segment as part of the polymer backbone. Thepolyether segment may be derived from polyethylene glycol (PEG). In someembodiments, the polyether segment is derived from a PEG having amolecular weight in the range of from about 200 to 10,000, preferablyfrom about 200 to about 3000.

In some embodiments, the triazole moieties in the polymer backbone mayprovide hard segments, which influence the properties of thepolymer-bioactive agent conjugates.

In some embodiments, it may be desirable for polymer-bioactive agentconjugates of one or more embodiments of the invention to bebiodegradable.

By being “biodegradable” in the context of the invention is meant thatthe polymer undergoes with the passage of time substantial degradationunder physiological conditions or in a biological environment. In otherwords, the polymer has a molecular structure that is susceptible tobreak down (i.e. a reduction in molecular weight) by chemicaldecomposition in a biological environment (e.g. within a subject or incontact with biological material such as blood, tissue etc), as opposedto physical degradation. Such chemical decomposition will typically bevia the hydrolysis of labile or biodegradable moieties that form part ofthe molecular structure of the polymer.

The presence of a biodegradable polymeric linker segment in the polymerbackbone may confer biodegradability to the polymer conjugates of theinvention.

Labile or cleavable functional groups present in the polymer backbonemay also be susceptible to degradation, leading to the production oflower molecular weight fragments upon erosion of the polymer conjugates.

Biodegradable polymer conjugates of the invention may comprise acombination of degradable groups. For example, the conjugates maycomprise a biodegradable polymeric linker, as well as cleavablefunctional groups, as part of the polymer backbone.

In some embodiments, polymer-bioactive agent conjugates of the inventionmay be formed by reacting a monomer of formula (IV):

where:

-   -   X may be the same or different at each occurrence and represents        a terminal functional group comprising an alkyne or an azide        functionality;    -   Q is independently selected at each occurrence and may be        present or absent and when present, represents a linking group;    -   R is an optionally substituted linear or branched hydrocarbon        and may comprise optionally substituted aromatic hydrocarbon or        heteroaromatic hydrocarbon;    -   Z is a cleavable linking group; and    -   D is a bioactive agent selected from the group consisting of        prostaglandin analogues and β-blockers,        with at least one monomer of complementary functionality.

In some embodiments, polymer-bioactive agent conjugates of the inventionmay be formed by reacting at least one monomer of formula (IV):

where X, Q, R, Z and D are as herein defined,with at least one monomer of complementary functionality.

In the monomer of formula (IV), the groups Q, R, Z and D may be selectedfrom any one of the moieties as described herein for such groups.

In one set of embodiments, the monomer of complementary functionalitymay be a monomer of formula (V):

A-LA]_(n)  (V)

where:

A may be the same or different at each occurrence and represents a groupcomprising a terminal functional group selected from the groupconsisting of an alkyne and an azide, wherein said terminal functionalgroup is complementary to the terminal functional group of X;

L is an optionally substituted linker group; and

n is an integer and is at least 1.

In another set of embodiments, the monomer of complementaryfunctionality may be a further monomer of formula (IV). In suchembodiments at least two monomers of formula (IV) may react together,provided the monomers of formula (IV) have complementary terminalfunctionality.

In some embodiments monomers of formula (IV) having complementaryterminal functionality may be homofunctional. That is, each of theco-monomers may comprise one type of terminal functional group. Theterminal functional groups of the co-monomers would be complementary andcapable of reacting with one another to form a triazole moiety. Forexample, one co-monomer of formula (IV) may comprise a terminalfunctional group comprising an alkyne functionality while the otherco-monomer of formula (IV) comprises a terminal functional groupcomprising an azide functionality. These co-monomers would be able tocopolymerise under appropriate conditions to form a polymer conjugatehaving triazole moieties in the polymer backbone.

Examples of complementary monomers of formula (IV) that are capable ofcopolymerising to form a polymer-bioactive agent conjugate are shown informula (IVa) and formula (IVb):

where:

-   -   Alk represents a terminal functional group comprising an alkyne        functionality;    -   Q is independently selected at each occurrence and may be        present or absent and when present, represents a linking group;    -   R is an optionally substituted linear or branched hydrocarbon        and may comprise optionally substituted aromatic hydrocarbon or        heteroaromatic hydrocarbon;    -   Z¹ is a cleavable linking group; and    -   D¹ is a bioactive agent selected from the group consisting of        prostaglandin analogues and β-blockers,

where:

-   -   Az represents a terminal functional group comprising an azide        functionality;    -   Q is independently selected at each occurrence and may be        present or absent and when present, represents a linking group;    -   R is an optionally substituted linear or branched hydrocarbon        and may comprise optionally substituted aromatic hydrocarbon or        heteroaromatic hydrocarbon;    -   Z² is a cleavable linking group; and    -   D² is a bioactive agent selected from the group consisting of        prostaglandin analogues and β-blockers.

One skilled in the art would appreciate that the terminal functionalgroups represented by Alk and Az in formulae (IVa) and (IVb) may bereversed. That is, the group Az may be present on formula (IVa) and thegroup Alk may be present on formula (IVb) in some embodiments.

The terminal functional groups represented by Alk and Az on theco-monomers of formula (IVa) and (IVb) can react to produce a triazolemoiety. The triazole moiety may be of formula (II), (III) or (IX) asdescribed herein.

A polymer-bioactive agent conjugate of the invention produced from thecopolymerisation of monomers of formula (IVa) and (IVb) may comprise amoiety of formula (Ib) as described herein. The monomers of formula(IVa) and (Vb) may react with one another in a mole ratio of 1:1.

The terminal functional groups represented by Alk in formulae describedherein may be straight chain aliphatic or cycloaliphatic groupscomprising an alkyne functionality. Cycloaliphatic terminal functionalgroups may comprise from 4 to 12 ring members, preferably from 7 to 8ring members. Cycloaliphatic alkyne containing terminal functionalgroups may be advantageous in strain-promoted catalyst freecycloadditions with azides to form triazole moieties.

A monomer—bioactive agent conjugate of formula (IVa) that may be used inpreparing the polymer conjugates of the invention may have one of thefollowing structures, (IVai) and (IVaii), where the alkyne functionalityis part of a terminal functional group as a terminal alkyne or aninternal alkyne:

A monomer—bioactive agent conjugate of formula (IVb) that may be used inpreparing the polymer conjugates of the invention may have the followingstructure (IVbi):

In monomers of formula (IVa) and (IVb), the groups Q and R may beindependently selected at each occurrence from any one of the moietiesdescribed herein for such groups.

The groups Z¹ and Z² in the monomers of formula (IVa) and (IVb)respectively are each cleavable linking groups, which may be the same ordifferent. Z¹ and Z² may each be independently selected from any one ofthe groups described herein for Z.

The groups D¹ and D² in the monomers of formula (IVa) and (IVb)respectively are each bioactive agents, which may be the same ordifferent. D¹ and D² may each be independently selected from any one ofthe groups described herein for D.

In some embodiments monomers of formula (IV) having complementaryterminal functionality may be heterofunctional and comprise at least twodifferent types of terminal functional groups. The terminal functionalgroups on the different monomers would be complementary and capable ofreacting with one another to produce a triazole moiety. The trizolemoiety may be selected from any of the formulae described herein forsuch moieties. A heterofunctional monomer may polymerise with itself(homopolymerise) or with another monomer of complementary functionality(copolymerise) under appropriate conditions to form a polymer-bioactiveagent conjugate.

An example of a monomer of formula (IV) that can polymerise to form apolymer-bioactive agent conjugate is shown in formula (IVc):

where:

-   -   Alk represents a terminal functional group comprising an alkyne        functionality;    -   Az represents a terminal functional group comprising an azide        functionality;    -   Q is independently selected at each occurrence and may be        present or absent and when present, represents a linking group;    -   R is an optionally substituted linear or branched hydrocarbon        and may comprise optionally substituted aromatic hydrocarbon or        heteroaromatic hydrocarbon;    -   Z is a cleavable linking group; and    -   D is a bioactive agent selected from the group consisting of        prostaglandin analogues and β-blockers.

Depending on the monomers used to prepare the polymer-bioactive agentconjugate, in some embodiments the polymer-bioactive conjugate of theinvention may comprise a repeating unit of formula (VIa) or formula(VIb):

wherein in (VIa) and (VIb), T, Q, R, Z, D and L are as defined herein.

A repeating unit of formula (VIa) or (VIb) may occur when a monomer offormula (IV) reacts with a complementary monomer of formula (V).

In some embodiments, the polymer-bioactive conjugate of the inventionmay comprise a repeating unit of formula (VIc):

wherein T, Q, R, Z¹, Z², D¹ and D² are as defined herein.

A repeating unit of formula (VIc) may occur when two complementarymonomers of formula (IV) react together.

A monomer which has a bioactive agent pendantly attached thereto isreferred to herein as a monomer—bioactive agent conjugate. An example ofa monomer-bioactive agent conjugate is shown in formula (IV), asillustrated above.

In another aspect, the present invention provides a monomer-bioactiveagent conjugate of formula (IV):

where:

-   -   X may be the same or different at each occurrence and represents        a terminal functional group comprising an alkyne or an azide        functionality;    -   Q is independently selected at each occurrence and may be        present or absent and when present, represents a linking group;    -   R is an optionally substituted linear or branched hydrocarbon        and may comprise optionally substituted aromatic hydrocarbon or        heteroaromatic hydrocarbon;    -   Z is a cleavable linking group; and    -   D is a bioactive agent selected from the group consisting of        prostaglandin analogues.

In the monomer-bioactive agent conjugate of formula (IV) each Xrepresents a group comprising a terminal functional group comprising analkyne or azide functionality. The terminal functional group in X may bethe same or different at each occurrence. Where the terminal functionalgroups (X) are the same, the monomer will generally be a diazide ordialkynyl monomer.

One skilled in the relevant art would understand that the terms “alkyne”and “azide” represent the following structures:

Alkyne: —C≡CH—C≡C—

Azide: —N═N⁺═N⁻

In one set of embodiments, the terminal functional group represented byX may comprise an optionally substituted straight chain aliphaticcomprising an alkyne functionality. In such embodiments, X may comprisethe alkyne functionality as a terminal alkyne. In one set ofembodiments, group X comprises a terminal alkyne functionality. Aterminal alkyne functionality may have a structure represented asfollows:

—C≡CH (terminal alkyne)

In one set of embodiments, the terminal functional group represented byX comprises an optionally substituted cyclic group comprising an alkynefunctionality. In such embodiments, the alkyne functionality may beregarded as an internal alkyne, as the alkyne functionality would bepart of the ring structure of the cyclic group. An internal alkyne mayhave a structure represented as follows:

—C≡C— (internal alkyne)

Internal alkynes contained in a cyclic group may be activated forparticipation in cycloaddition reactions by the presence of one or moresubstituent groups (e.g. electron withdrawing groups) present on thecyclic structure or by means of ring strain in the cyclic structure.

In one set of embodiments when X comprises an optionally substitutedcyclic group comprising an alkyne functionality, the group may have astructure of formula (XV):

where:

each M represents a ring atom and is independently selected from thegroup consisting of carbon (C), nitrogen (N), oxygen (O) and sulphur(S), with the proviso that at least 3 M is carbon; and

p is 1, 2 or 3, preferably p is 2.

In one embodiment, p is 1 and least one M is selected from the groupconsisting of N, O and S, preferably S.

In another embodiment, p is 2 and each M is carbon (C) or at least one Mis selected from the group consisting of N, O and S, preferably S.

In another embodiment, p is 3 and each M is carbon (C).

Optional substituents that may be present in formula (XV) may beselected from the group consisting of hydroxy (—OH), —Oalkyl, alkyl,halo (preferably fluoro), cycloalkyl, heterocycloalkyl, aryl andheteroaryl. Cycloalkyl, heterocycloalkyl, aryl and heteroarylsubstituent groups may each independently comprise from 3 to 6 ringatoms and may be fused to the cyclic group. The optional substituentsmay be located on any ring atom of the cyclic group. In one preference,one or more optional substituents are located at a ring atom ortho tothe alkyne functionality.

In one set of embodiments X comprises a cycloalkyne of formula XVI

wherein the cycloalkyne comprises from 7 to 9 constituent ring membersselected from carbon and optionally including one or two heteroatomgroups selected from sulfur and the group N—R^(t) wherein R^(t) ishydrogen, C₁ to C₆ alkyl or the group (Q) and wherein the ring isoptionally substituted with at least one substituent selected from thegroup consisting of

hydroxy (preferably from 0 to 2 hydroxy);

oxo (i.e. ═O) (preferably 0 or 1 oxo);

halo (preferably from 0 to 2 halo selected from chloro, bromo and fluoroand most preferably fluoro);

C₁ to C₆ alkoxy (preferably from 0 to 2 C₁ to C₆ alkoxy); and

rings fused with said ring of 7 to 9 constituent members wherein saidfused rings include 0 to 3 rings each fused with said 7 to 9 memberedring and selected from benzene, cyclopropanone, and cyclopropane

wherein the fused benzene and cyclopropane rings are optionally furthersubstituted with from one to three substituents selected from the groupconsisting of C₁ to C₆ alkyl, halo (preferably from 0 to 2 halo selectedfrom chloro, bromo and fluoro and most preferably fluoro) and C₁ to C₆alkoxy;and wherein at least one ring member selected from nitrogen and carbonis bonded to Q.

The moiety “Q” present in formulae (I), (Ib), (IIa), (IIb), (IIIa),(IIIb), (IV), (IVa), (IVb), (IVc), (VIa), (VIb), (VIc), (IXa) and (IXb)defined herein may be present or absent at each occurrence. Whenpresent, Q represents a linking group, and is independently selected ateach occurrence. Examples of Q that may be present in formulae (I),(Ib), (IIa), (IIb), (IIIa), (IIIb), (IV), (IVa), (IVb), (IVc), (VIa),(VIb), (VIc), (IXa) and (IXb) are described below.

In some embodiments of formulae (I), (Ib), (IIa), (IIb), (IIIa), (IIIb),(IV), (IVa), (IVb), (IVc), (VIa), (VIb), (VIc), (IXa) or (IXb), two Qare present and each Q is attached to the group “R”. In otherembodiments of formulae (I), (Ib), (IIa), (IIb), (IIIa), (IIIb), (IV),(IVa), (IVb), (IVc), (VIa), (VIb), (VIc), (IXa) or (IXb), one Q ispresent and one Q is absent.

In one set of embodiments, the linking group Q present in formulaedefined herein may comprise a linking moiety. In some embodiments, thelinking moiety may be an optionally substituted aliphatic moiety. Asuitable aliphatic linking moiety may be selected from a saturated C₁ toC₂₀, C₁ to C₁₀ or C₁ to C₆ straight or branched aliphatic moiety. Thealiphatic moiety may be optionally substituted by one or moresubstituents.

In monomer-bioactive agent conjugates described herein, the presence ofa linking group Q connected to a terminal functional group comprising analkyne or azide functionality may facilitate polymerisation of themonomer by reducing steric crowding around the terminal functionalgroup.

In some embodiments, in the monomer of formula (IV), each Q-X is a groupof formula (VII):

where:

X is a terminal functional group comprising an alkyne or an azidefunctionality; and

m is an integer in the range of from 0 to 10.

In some embodiments of formula (VII), m is an integer in the range offrom 1 to 5.

In some embodiments the linking group Q present in formulae definedherein may comprise a functional group. The functional group may bepresent in addition to the linking moiety. Thus, the linking moiety andthe functional group together form the linking group Q.

In one set of embodiments Q comprises a functional group selected fromthe group consisting of an amide, ether, ester, urethane, urea, andcarbonate ester functional group.

In some embodiments, the linking group Q may be represented by formula(VIII):

where:

Y represents a functional group; and

M represents a linking moiety.

In one embodiment, M may be an optionally substituted aliphatic linkingmoiety.

In monomers of formula (IV), when Q comprises a functional group, thegroup Q-X may be represented by formula (VIIIa):

where:

Y is a functional group;

M is a linking moiety; and

X is a terminal functional group comprising an alkyne or an azidefunctionality.

In some embodiments, M is an optionally substituted saturated C₁ to C₂₀,C₁ to C₁₀ or C₁ to C₆ straight or branched aliphatic linking moiety.

In some embodiments the group Q-X in monomers of formula (IV) may berepresented by formula (VIIIb):

where:

Y is a functional group;

X is a terminal functional group comprising an alkyne or an azidefunctionality; and

m is an integer in the range of from 0 to 10.

In some embodiments of formula (VIIIb), m is an integer in the range offrom 1 to 5.

The functional group represented by Y in formulae (VIII), (VIIIa) and(VIIIb) may be selected from the group consisting of an amide, ether,ester, urethane, urea, and carbonate ester functional group.

In some embodiments, in the monomer of formula (IV), Q is present andeach Q-X is independently selected from the following group:

When a monomer-bioactive agent conjugate having a linking group Q isused to prepare polymer conjugates of the invention, the linking group Qbecomes incorporated into the polymer backbone. Thus any linkingmoieties and functional groups present in Q become part of the backboneof the polymer conjugate.

When Q comprises a functional group (represented by Y in formulaedefined herein) such as an amide, ether, ester, urethane, urea, andcarbonate ester functional group, such functional groups will generallybe cleavable functional groups and can provide points for erosion ordegradation in the polymer backbone when a monomer-bioactive agentconjugate comprising such groups is used to form the polymer conjugate.The presence of cleavable groups derived from the functional groups inthe polymer backbone can facilitate breakdown of the polymer conjugate,allowing formation of lower molecular weight polymer fragments.

The moiety “R” present in formulae (I), (Ib), (IIa), (IIIb), (IIIa),(IIIb), (IV), (IVa), (IVb), (IVc), (VIa), (VIb), (VIc), (IXa) and (IXb)described herein represents an optionally substituted linear or branchedhydrocarbon. In some embodiments the hydrocarbon may have between 1 and12 carbon atoms, for example between 1 and 6 carbon atoms or 2 or 3carbon atoms. The hydrocarbon may be partially or completely saturatedor unsaturated (including moieties that are aromatic). Specific examplesof R include a moiety having one of the following structures:

One skilled in the art would appreciate that when a monomer-bioactiveagent conjugate comprising a moiety “R” is polymerised to form apolymer-bioactive agent conjugate, then R becomes part of the polymerbackbone of the conjugate.

The moiety “Z” present in monomer-bioactive conjugates of formula (IV)represents a cleavable linking group as described herein.

The moiety “D” present in monomer-bioactive agent conjugates of formula(IV) represents a releasable bioactive agent as described herein. Whilethe bioactive agent is releasable while conjugated to the monomer, itwould be understood however that the bioactive agent is only intended tobe released after the monomer-bioactive agent conjugate has reacted toform the polymer conjugate.

Examples of dialkynyl monomer conjugates with prostaglandin analogues asthe pendant conjugated bioactive agent linked through the 1-carboxylicacid are shown below:

Examples of diazide monomer conjugates with prostaglandins as thependant conjugated bioactive agent linked through the 1-carboxylic acidare shown below:

Examples of dialkyne, diazide and azide/alkyne monomer conjugates withβ-blockers as the pendant conjugated bioactive agent linked through thehydroxy group are shown below:

Monomer-bioactive agent conjugates of the invention may be prepared bycovalently coupling a bioactive agent to a suitably functionalisedalkyne or azide containing precursor compound. Some examples of alkyneprecursor compounds that may be used to prepare monomer-bioactive agentconjugates of the invention are shown below:

In the above dialkyne compounds, the carboxylic acid or hydroxylfunctional groups are capable of covalently reacting with acomplementary functional group in a bioactive agent, to allow thebioactive agent to be coupled to the dialkyne compound to produce amonomer-bioactive agent conjugate that may participate in clickchemistry reactions. One skilled in the relevant art would appreciatethat one or more of the alkyne functionalities in the above compoundsmay be replaced by azide functional groups.

In one set of embodiments, the monomer-bioactive agent conjugate offormula (IV) is preferably a dialkyne monomer. Accordingly, the group Xin formula (IV) are each terminal functional groups comprising alkynefunctionality. Monomer-bioactive agent conjugates comprising terminalfunctional groups comprising alkyne functionality are preferred as suchmonomer-bioactive agents are safer to process than their diazidecounterparts.

As discussed above, in some embodiments, the polymer-bioactive agentconjugate of the invention can be obtained by polymerising at least onemonomer of formula (IV) with at least one monomer of formula (V)described above.

In some embodiments, the polymer-bioactive agent conjugate of theinvention is a copolymer of at least one monomer of formula (IV):

where:

-   -   X may be the same or different at each occurrence and represents        a terminal functional group comprising an alkyne or an azide        functionality;    -   Q is independently selected at each occurrence and may be        present or absent and when present, represents a linking group;    -   R is an optionally substituted linear or branched hydrocarbon        which may include optionally substituted aromatic hydrocarbon        and heteroaromatic hydrocarbon;    -   Z is a cleavable linking group; and    -   D is a bioactive agent selected from the group consisting of        prostaglandin analogues and β-blockers;        and at least one monomer of formula (V):

A-LA]_(n)  (V)

where:

A may be the same or different at each occurrence and represents a groupcomprising a terminal functional group comprising an alkyne or an azidefunctionality, wherein said terminal functional group is complementaryto the terminal functional group of X;

L is an optionally substituted linker group; and

n is an integer and is at least 1.

The groups A, L and n in formula (V) are further discussed below.

The covalent reaction between a terminal functional group (X) on themonomer of formula (IV) with a complementary terminal functional groupon the monomer of formula (V) produces a triazole moiety. Triazolemoiety may be of formulae (II), (III) or (IX) as described herein.Preferably, the triazole moiety is a 1,4-regioisomer as represented byformulae (II), (IIa) and (IIb), or a 1,5-regiosiomer as represented byformulae (III), (IIIa) and (IIIb), as described herein. It will beunderstood by those skilled in the art that the 1,4-regioisomer can beformed using a copper catalyst during the reaction of the monomers andthe 1,5-regioisomer can be formed using a rhuthenium catalyst during thereaction of the monomers (J. Am. Chem. Soc., 2005, 127 (46), pp15998-15999, Ruthenium-Catalyzed Cycloaddition of Alkynes and OrganicAzides, Zhang et al, Boren et al J Am Chem Soc 2008; 130: 8923-8930).

The triazole may also be formed through the use of metal-free, strainpromoted azide-alkyne cycloaddition (SPAAC) and does not require acatalyst. The regiochemistry of SPAAC is mixed with both 1,4 and 1,51,2,3 triazoles being formed. The preparation of cycloalkyne andheterocyclic alkyne compounds and their use in SPAAC click chemistry hasbeen described in a number of publications, including:

-   Jewett et al. “Cu-free click cycloaddition in chemical biology”,    Chem. Soc. Rev., 2010, 39, 1272-1279;-   Baskin et al. “Copper-Free Click Chemistry: Bioorthogonal Reagents    for Tagging Azides” Aldrichimica Acta, Vol. 43, No. 1 2010, 15-23;-   Recer et al. “Click Chemistry beyond Metal-Catalyzed Cycloaddition”    Angew. Chem. Int. Ed., 2009, 48, 4900-4908.-   Almeida et al. “Thiacycloalkanes for copper-free click chemistry”,    Angewandte Chemie Int. Ed. 2012, 51, 2443-2447; and-   Sletten et al., “Ahydrophilic Azacyclooctyne for Cu-Free Click    Chemistry Org. Let. Vol. 10, No. 14, 2009, 3097-3099.

The methods and compounds described in these references may be used inpreparation of the cycloalkyne of formula XVI having a wide range ofsubstituents without undue experimentation. The method of the inventionmay be used to provide a wide range of polymers of formula IX withtriazole units such as in formula IV. It is an advantage of thisembodiment that the copolymerization reaction to form triazole groupsmay in many cases take place without the need for a catalyst.

The monomers of formula (IV) and (V) may react with one another in amole ratio of 1:1. In some embodiments, it may be desirable to have amolar excess of a monomer comprising terminal functional groups havingalkynyl functionality. Without wishing to be limited by theory, it isthought that azide containing functional groups may be toxic to abiological environment. As a result, the use of a molar excess ofmonomer comprising alkynyl functional groups to prepare the conjugatesmay help to ensure that residual unreacted azide functional groups donot remain in the structure of the conjugates.

In the monomer of formula (V), A represents a group comprising aterminal functional group comprising an alkyne or an azidefunctionality. The azide or alkyne functionality present in terminalfunctional group of moiety “A” is complementary to the azide or alkynefunctionality present in the terminal functional group of X in formula(IV), such that upon reaction of the functional groups in A and X underclick reaction conditions, a triazole moiety is formed.

In the monomer of formula (V) n is an integer and is at least 1. In someembodiments, n is an integer selected from the group consisting of 1, 2,3, 4, 5, 6, 7 and 8. In one form, in the monomer of formula (V) n is 1or 2. The monomer of formula (V) comprises at least two A moieties,which may be the same or different at each occurrence.

When n is 1, the monomer of formula (V) is difunctional and comprisestwo A moieties. When n is 2 or more, the monomer of formula (V) ismultifunctional and comprises 3 or more A moieties. In such embodiments,the monomer of formula (V) may be a branched monomer. Three or more Amoieties may be present when L is branched. Monomers of formula (V)comprising at least three terminal functional groups have the potentialto provide branched architectures for the polymer conjugates of theinvention.

As used herein, the term “group comprising a terminal functional group”encompasses embodiments where the group represents the terminalfunctional group per se, as well as embodiments where the terminalfunctional group is part of a larger chemical group.

The moiety “L” in formula (V) represents an optionally substitutedlinker group. In some embodiments L may be a divalent group.Alternatively, L may be mulitvalent and be a branched group. When amonomer of formula (IV) and (V) copolymerise, L forms a linker segmentin the polymer backbone of the conjugate.

In some embodiments, L may comprise a linker moiety selected from thegroup consisting of optionally substituted linear or branched aliphatichydrocarbon, optionally substituted carbocyclyl, optionally substitutedheterocyclyl, optionally substituted aryl, optionally substitutedheteroaryl, an optionally substituted polymeric segment, andcombinations thereof.

Optionally substituted linear or branched aliphatic hydrocarbon linkermoieties may be selected from optionally substituted C₁ to C₂₀, C₁ toC₁₀ or C₁ to C₆ linear or branched aliphatic hydrocarbons. The aliphatichydrocarbons may be saturated or unsaturated hydrocarbon.

Optionally substituted carbocyclyl linker moieties may have from 3 to12, 3 to 8 or 5 to 6 carbon ring members.

Optionally substituted heterocyclyl linker moieties may have from 3 to12, 3 to 8 or 5 to 6 ring members and 1, 2, 3, 4 or more heteroatoms asa part of the ring. The heterotoms may be independently selected fromthe group consisting of O, N and S.

Optionally substituted aryl linker moieties may have from 3 to 12, 3 to8 or 5 to 6 carbon ring members and at least one unsaturation.

Optionally substituted heteroaryl linker moieties may have from 3 to 12,3 to 8 or 5 to 6 ring members and 1, 2, 3, 4 or more heteroatoms as apart of the ring. The heterotoms may be independently selected from thegroup consisting of O, N and S. The heteroaryl linker moiety also has atleast one unsaturation.

Optionally substituted polymeric linker moieties may comprise anysuitable polymer or copolymer. In some embodiments, it can be desirablefor the polymeric moiety to comprise a biocompatible and/orbiodegradable polymer. One skilled in the relevant art would be able toselect suitable biocompatible and/or biodegradable polymers. Exemplarybiocompatible polymers may include polyethers, polyesters, polyamides,polyurethanes, and copolymers thereof, such as poly(ether-esters),poly(urethane-ethers), poly(urethane-esters), poly(ester-amides) and thelike. Preferred biocompatible polymers are polyethers, polyesters,polyurethanes, and copolymers thereof.

Exemplary polyethers include polymers of C₂ to C₄ alkylene diols, suchas polyethylene glycol and polypropylene glycol, preferably polyethyleneglycol.

Exemplary polyesters include polycaprolactone, poly(lactic acid),poly(glycolic acid) and poly(lactic-co-glycolic acid).

In one form, the polymeric linker moiety may comprise a biodegradablepolymer. In general, biodegradable polymers comprise at least onebiodegradable moiety. The biodegradable moiety may be selected from thegroup consisting of an ester, an amide, a urethane and a disulfidemoiety. The biodegradable polymers comprise a combination of suchmoieties. One skilled in the relevant art would understand that suchbiodegradable moieties are capable of undergoing degradation or cleavagein a biological or physiological environment.

Optionally substituted polymeric linker moieties may be of any suitablemolecular weight, and the desired molecular weight may depend on thetype of polymer and its properties. In some embodiments, L comprises apolymeric moiety having a molecular weight of not more than 1500.

In one set of embodiments, L comprises a polyether linker moiety derivedfrom polyethylene glycol (PEG). The polyether segment may be derivedfrom a PEG of suitable molecular weight. In some embodiments, the PEGhas a molecular weight in the range of from about 200 to 10,000,preferably from about 200 to about 3000.

In one set of embodiments, L comprises a linker moiety derived fromlysine, including the ethyl ester of lysine such asethyl-2,6-bis(((3-azidopropoxy)carbonyl)amino)hexanoate (ELDN₃) thedi(1-pentynol)urethane of the ethyl ester of lysine and thedi(1-pentynol)urethane of the 1-pentynol ester of lysine.

In some embodiments, the group “L” in the formula (V) may comprise afunctional group. The functional group may be selected from the groupconsisting of an amide, ether, ester, urethane, urea, and carbonateester functional group. Such functional groups will generally becleavable functional groups, which can degrade in a biologicalenvironment.

In one set of embodiments, L comprises a linker moiety and a functionalgroup.

In some embodiments, the monomer of formula (V) may have a structure offormula (Va):

A-B—YB-A]_(n)  (Va)

where:

A may be the same or different at each occurrence and represents a groupcomprising a terminal functional group comprising an alkyne or an azidefunctionality, wherein the alkyne or azide functionality in the terminalfunctional group is complementary to the alkyne or azide functionalityin a terminal functional group X present on a monomer of formula (IV);

Y represents a functional group;

B may be present or absent and when present represents an optionallysubstituted linker moiety; and

n is 1 or 2.

In some embodiments, the monomer of formula (V) may have a structure offormula (Vb):

A-Y—BY-A]_(n)  (Vb)

where:

A may be the same or different at each occurrence and represents a groupcomprising a terminal functional group comprising an alkyne or an azidefunctionality, wherein the alkyne or azide functionality in the terminalfunctional group is complementary to the alkyne or azide functionalityin a terminal functional group X present on a monomer of formula (IV);

Y may be the same or different at each occurrence and represents afunctional group;

B represents an optionally substituted linker moiety; and

n is at least 1, preferably n is 1 or 2.

In some embodiments of formula (Vb), B represents a branched linkermoiety (such as branched aliphatic linker moiety) and n is at least 2.In such embodiments, B comprises three or more —Y-A substituent groups.

In some embodiments of formula (Vb), B represents a branched linkermoiety (such as branched aliphatic linker moiety) and n is 2. In suchembodiments, B comprises three —Y-A substituent groups

In some embodiments of formula (Vb), B represents an optionallysubstituted polymeric linker moiety. The polymeric linker moiety maycomprise a biocompatible and/or biodegradable polymer as describedherein. In one set of embodiments B preferably comprises a polyether,polyester, polyamide, polyurethane, or copolymer thereof.

In one set of embodiments of formule (Vb), B is a polymeric linkermoiety derived from polyethylene glycol (PEG). The polyethylene glycolmoiety preferably has a molecular weight in the range of from about 200to 10,000, more preferably from about 200 to 3000.

The group Y in formulae (Va) and (Vb) may be independently selected fromthe group consisting of an amide, ether, ester, urethane, urea, andcarbonate ester functional group, preferably a ester or urethanefunctional group.

In monomers of formulae (Va) and (Vb), the combination of the moieties Band Y together form the linker group L, as shown in formula (V).

Some specific examples of monomers of formula (V) that may be used toprepare polymer-bioactive agent conjugates of the invention is shown inTable 3:

TABLE 3

In some structures shown in Table 3, n represents the number ofrepeating units and is an integer that may be selected from 0 and atleast 1.

An example of a polymer-bioactive agent conjugate of the inventionformed with a dialkyne monomer of formula (IV) and a diazide monomer offormula (V) is shown in Scheme 1 below:

Another example of a polymer-bioactive agent conjugate of the inventionformed with a dialkyne monomer of formula (IV) and a diazide monomer offormula (V) is shown in Scheme 2 below:

An example of a polymer-bioactive agent conjugate of the inventionformed with a diazide monomer formula (IV) and a dialkyne monomer offormula (V) is shown in Scheme 3 below:

Scheme 4 illustrating general structures of polymer-bioactive agentconjugates in accordance with embodiments of the invention that areformed with co-monomers comprising different terminal functional groupsand under different click chemistry reaction conditions.

One skilled in the relevant art would understand that the constituentcomponents of each monomer, for example the cleavable linking group ofthe monomer of formula (IV) or the linker group of the monomer offormula (V), can be varied to allow the properties of thepolymer-bioactive agent conjugate to be tailored to suit particularapplications.

Polymer conjugates of the invention may contain more than one type ofbioactive agent.

Polymer conjugates of the invention may contain more than one type oflinker segment in the polymer backbone.

Some specific examples of monomer-bioactive agent conjugates, andco-monomers that may be used in the preparation of polymer-bioactiveagent conjugates of the invention are shown below:

As discussed above, polymer-bioactive agent conjugates of the inventionmay comprise a moiety of formulae (VIa), (VIb) or (VIc). Moieties offormulae (VIa), (VIb) and (VIc) may be formed when a monomer of formula(IV) polymerises with a monomer of complementary functionality. Themonomer of complementary functionality may be a monomer of formula (V),or it may be a further monomer of formula (IV). As illustrated above,moieties of formulae (VIa), (VIb) and (VIc) comprise Q and in the caseof formulae (VIa) and (VIb), also comprise L.

Polymer-bioactive agent conjugates of the invention may be a copolymerof a mixture of monomers, such as for example, a mixture of two or moremonomer conjugates of formula (IV), optionally, or additionally, with amixture of two or more complementary monomers of formula (V). Theability to use a monomer composition comprising a mixture of differenttypes of monomer can allow the properties of the polymer conjugates tobe tailored for different applications. For example, thecopolymerisation of at least two different monomer conjugates of formula(IV), where the monomer conjugates comprise prostaglandin analogues andβ-blockers as the bioactive agent D, can allow a single polymerconjugate comprising a mixture of prostaglandin analogues and β-blockersas pendant bioactive agents to be obtained.

When Q and L comprise functional groups, conjugates of the invention maycomprise a polymer backbone having a plurality of cleavable functionalgroups. The cleavable functional groups will generally form part of thepolymer backbone and may be located on either one side or both sides ofa triazole moiety. Cleavage of the functional groups in the polymerbackbone may therefore release a triazole containing fragment whenpolymer conjugates of the invention biodegrade. For example, when Qand/or L comprises ester functional groups, a triazole fragment producedas a by-product of polymer degradation could be a dihydroxy triazole, adiacid triazole or hydroxyl-acid triazole, depending on the direction ofthe ester.

The invention also provides a method for preparing a polymer—bioactiveagent conjugate comprising as part of its polymer backbone a moiety ofgeneral formula (I):

by reacting at least one monomer of formula (IV):

with at least one complementary monomer of formula (V):

A-LA]_(n)  (V)

under click cycloaddition reaction conditions.

In embodiments of the invention, click cycloaddition reactions may becatalyzed by a metal. Exemplary metals include copper (e.g. Cu(I)) whichmay be generated in situ from Cu(II) and ascorbic acid), and ruthenium(e.g. Ru(II)). Other metals that can be used include, but are notlimited to, Ag, Ni, Pt, Pd, Rh, and Ir. In addition a metal free, strainpromoted azide-alkyne cycloaddition (SPAAC). In this embodiment, nometal catalyst is required as the alkyne is activated by means ofincorporation of the alkyne functionality into a strained ring.

In some embodiments, one or more further monomers may be employed in thesynthesis of the polymer-bioactive conjugates of the invention. Whenused, the one or more further monomers may act as chain extenders, toincrease the molecular weight or to tailor the properties of the polymerbackbone, for example, by introducing flexibility or hard or softsegments into the polymer backbone. In order to be incorporated into thepolymer backbone, the one or more further monomers will be required tohave terminal functional groups selected from alkyne and azidefunctional groups. Depending on the nature of the terminal functionalgroup, the one or more further monomers will be capable of reacting withat least one co-monomer selected from the group consisting of a formula(IV) and a monomer of formula (V).

It is possible to some extent to control the molecular weight of thepolymer-bioactive agent conjugate, its degree of branching (throughcontrol of monomer functionality) and its end group functionality byadjusting the molar ratio and the functionality of the monomers employedin the conjugate synthesis.

Irrespective of the manner in which the polymer—bioactive agentconjugates are prepared, all repeat units that make up the polymerbackbone will be coupled via a triazole moiety.

In one embodiment, the methods of the invention allow the formation ofbiodegradable moieties with multiple bioactive agents, known loadings,evenly distributed bioactive agents in the polymer chain, predeterminedrelative proportions and predetermined relative positions.

Polymer-bioactive agent conjugates in accordance with the invention canadvantageously be prepared such that they are suitable foradministration to a subject (i.e. suitable for in vivo applications).

According to one embodiment there is provided a method of delivering abioactive agent to a subject, the method comprising administering to thesubject a polymer-bioactive agent conjugate in accordance with theinvention.

By the polymer conjugate being “suitable” for administration to asubject is meant that administration of the conjugate to a subject willnot result in unacceptable toxicity, including allergenic responses anddisease states. By the term “subject” is meant either an animal or humansubject.

By “administration” of the conjugate to a subject is meant that thecomposition is transferred to the subject such that the bioactive agentwill be released. The prostaglandin analogues and β-blockers areintended to use in the treatment of eye disorders associated withincreased intraocular pressure, such as glaucoma, it is preferred thatthe polymer conjugate is administered to an affected eye of a subject.Administration to the eye may be by way of intracameral orsubconjunctival administration.

The polymer conjugates may be provided in particulate form and blendedwith a pharmacologically acceptable carrier to facilitateadministration. By “pharmacologically acceptable” is meant that thecarrier is suitable for administration to a subject in its own right. Inother words, administration of the carrier to a subject will not resultin unacceptable toxicity, including allergenic responses and diseasestates. The term “carrier” refers to the vehicle with which theconjugate is contained prior to being administered.

As a guide only, a person skilled in the art may consider“pharmacologically acceptable” as an entity approved by a regulatoryagency of a federal or state government or listed in the US Pharmacopeiaor other generally recognised pharmacopeia for use in animals, and moreparticularly humans. Suitable pharmacologically acceptable carriers aredescribed in Martin, Remington's Pharmaceutical Sciences, 18th Ed., MackPublishing Co., Easton, Pa., (1990).

The polymer bioactive agent conjugates may also form part of or beformed into an article or device, or be applied as a coating on anarticle or device, and implanted in a subject. By being “implanted” ismeant that the article or device is totally or partly introducedmedically into a subject's body and which is intended to remain thereafter the procedure.

Suitable dosage amounts of the bioactive agents and dosing regimens ofthe polymer conjugates can be determined by a physician and may dependon the particular condition being treated, the rate of release of theagent form the polymer backbone, the severity of the condition as wellthe general age, health and weight of the subject.

The form of the polymer-bioactive agent conjugate may be adjusted to besuited to the required application such as a coating, film, pellet,capsule, fibres, laminate, foam etc. The difference in the form of theconjugate provides a means to alter the release profile of the bioactiveagent. For example the amount of polymer and bioactive agent may be thesame in two different structures however the differences in the surfacearea to volume, rates of hydration and diffusion paths from thedifferent physical forms or structures can result in different rates ofbioactive agent release from essentially the same polymer.

The adjustment of the form of the polymer conjugate to suit theapplication and further to adjust the form to further control bioactiveagent release provides an additional advantage over purely compositionaland polymer structural means to control the release profile of thebioactive agent.

Some of the compositional/structural means to control the release of thebioactive agent include: controlling the loading of the bioactive;composition of the other comonomers to adjust criteria such ashydrophobicity, flexibility, susceptibility to degradation, ability ofthe fragments to autocatalyse the polymer degradation, thermal stabilityof the polymer, mouldability, polymer solubility to assist casting etc.

In one set of embodiments, the bioactive agent may be released from thepolymer conjugate such that it provides for a sustained bioactivedelivery system. Such a delivery system may in its simplest form be thepolymer conjugate provided in a desired shape, for example a pellet ormore intricate shape. To promote surface area contact of the polymerconjugate under physiological conditions or with a biologicalenvironment, it may also be provided in the form of a foamed product ora coating on substrate.

By “sustained bioactive moiety delivery” is meant that the bioactiveagent is released from the conjugate over a period of time, for exampleover a period of 10 or more minutes, 30 or more minutes, 60 or moreminutes, 2 or more hours, 4 or more hours, 12 or more hours, 24 or morehours, 2 or more days, 5 or more days, 10 or more days, 30 or more days,2 or more months, 4 or more months or over 6 or more months.

Polymer-bioactive agent conjugates of the present invention may beincorporated into drug delivery systems, therapeutic articles, devicesor preparations, and pharmaceutical products for the treatment of ocularhypertension.

The polymer-bioactive agent conjugates of the present invention may beblended with one or more other polymers (for example, biodegradablepolymers).

The present invention also provides a sustained drug delivery systemcomprising a polymer-bioactive agent conjugate of the invention. In oneembodiment, the sustained drug delivery system may be in the form of animplant. The sustained drug delivery system may enable the prostaglandinanalogues and/or β-blockers to be administered over a sustained periodof time, such as for example, for at least 15 days, for at least 30days, for at least 45 days, for at least 60 days, or for at least 90days. A sustained release drug delivery system may be a more convenientway to administer the prostaglandin analogues and/or β-blockers, as itenables therapeutic levels of the drug to be continuously administeredover an extended period time and allows the drug therapy schedule to bematched with a patient's visitation schedule to a medical or healthpractitioner.

Polymer-bioactive agent conjugates in accordance with the invention canbe formed into an article or device. The article or device may befabricated in a range of forms. Suitably, the article or device is amedical device, preferably an ocular implant. The polymer conjugates inaccordance with the invention can also be incorporated or made intocoatings for target in vitro and in vivo applications.

The polymer-bioactive agent conjugates in accordance with the inventioncan be formed into an article or device that is suitable foradministration to the eye.

In some embodiments, a polymer-bioactive agent conjugate may be in theform of a solid article (such as a particle, rod or pellet), asemi-solid, a deformable solid, a gel, or a liquid, for placement in theeye of the subject.

In another aspect, the present invention provides an ocular implant forthe treatment of glaucoma comprising a polymer-bioactive agent conjugateof any one of the embodiments described herein.

In one form, the implant is a rod-shaped and is able to be housed withinthe lumen of a needle, such as a 20 to 23 gauge needle. The outerdiameter of the implant would be less than 0.5 mm, preferably about 0.4mm and more preferably 0.3 mm. The length of the implant can be selectedto deliver the required dose of drug.

The implant can be of a number of different structural forms. The ocularimplant could be a solid, a semi-solid or even a gel. A solid implantwould comprise material with a glass transition temperature (as measuredby differential scanning calorimetry) above 37° C., a semi-solid wouldhave a glass transition temperature at or just below 25-37° C. A gelcould be formed by appropriate formulation of the polymer conjugate withan appropriate plasticiser. In one set of embodiments, the implant couldbe a hydrogel.

In yet another aspect the present invention provides an injectablearticle for placement in an eye of the subject, wherein the injectablearticle comprises a polymer-bioactive agent conjugate of any one of theembodiments described herein. In one form, the injectable article is aninjectable gel.

It is contemplated that an ocular implant may be a bi-component polymerstructure where the polymer-bioactive agent conjugate can either beincorporated in the outer or inner layers of the bi-component structure.Incorporating the polymer-bioactive agent conjugate in the outer layercould be done to give a measured dose. Additionally the inner polymerlayer could be to provide structural integrity to allow the delivery viathe needle. Additionally the inner polymer could be designed to degradeeither faster or slower than the polymer conjugate layer. This could beto alter the rate of bioerosion or the implant.

Possible means for producing rod-shaped implants include:

-   -   Melt extrusion of the polymer-bioactive agent conjugate or a        material containing the polymer-bioactive agent conjugate        through a shaped die.    -   Simultaneous bi-component extrusion of the polymer-bioactive        agent conjugate and other materials forming the outer or inner        layers through an appropriate die.    -   Sequential overcoating extrusion of one polymer later with        another. For example a core polymer fibre of PLGA could be melt        overcoated with a polymer containing the polymer-bioactive agent        conjugate.    -   It is also possible to solution coat an appropriate inner        polymer carrier material (e.g. PLGA) with a solution containing        the polymer-bioactive agent conjugate.

In another aspect, the present invention provides an ocular implant forthe treatment of glaucoma in a subject comprising a polymer-drugconjugate of any one of the embodiments described herein. In someembodiments, the implant is in the form of a solid, semi-solid, gel orliquid suitable for placement in the eye of the subject.

In yet another aspect the present invention provides a pharmaceuticalproduct for the treatment of a glaucoma in a subject, saidpharmaceutical product comprising a polymer-bioactive agent conjugate ofany one of the embodiments described herein. The pharmaceutical productmay be an ocular implant or drug delivery system for the treatment ofglaucoma. In one form, the pharmaceutical product is an implant in theform of a solid article, semi-solid, deformable solid, gel (includinghydrogel), or liquid for placement in the eye of a subject.

In yet another aspect the present invention provides an injectablearticle for placement in an eye of the subject, wherein the injectablearticle comprises a polymer-bioactive agent conjugate of any one of theembodiments described herein. In one form, the injectable article is inthe form of a gel.

In another aspect, there is provided a method for the treatment ofglaucoma in a subject suffering glaucoma in one or both eyes, the methodcomprising administering a polymer-bioactive agent conjugate of any oneof the embodiments described herein to an eye afflicted with glaucoma.

In one set of embodiments, the polymer-bioactive agent conjugate iscontained in a solid article and method comprises implanting the articlein an affected eye of a subject. In one set of embodiments, the methodcomprises depositing the solid article in the lumen of a needle andinjecting the article into the eye from the needle.

In another aspect, there is provided use of a polymer-bioactive agentconjugate of any one of the embodiments described herein in themanufacture of a pharmaceutical product for the treatment of glaucoma.In one set of embodiments, the pharmaceutical product is in the form ofan ocular implant. The ocular implant is a solid article and may beinjectable.

In this specification “optionally substituted” is taken to mean that agroup may or may not be substituted or fused (so as to form a condensedpolycyclic group) with one, two, three or more of organic and inorganicgroups (i.e. the optional substituent) including those selected from:alkyl, alkenyl, alkynyl, carbocyclyl, aryl, heterocyclyl, heteroaryl,acyl, aralkyl, alkaryl, alkheterocyclyl, alkheteroaryl, alkcarbocyclyl,halo, haloalkyl, haloalkenyl, haloalkynyl, haloaryl, halocarbocyclyl,haloheterocyclyl, haloheteroaryl, haloacyl, haloaryalkyl, hydroxy,hydroxyalkyl, hydroxyalkenyl, hydroxyalkynyl, hydroxycarbocyclyl,hydroxyaryl, hydroxyheterocyclyl, hydroxyheteroaryl, hydroxyacyl,hydroxyaralkyl, alkoxyalkyl, alkoxyalkenyl, alkoxyalkynyl,alkoxycarbocyclyl, alkoxyaryl, alkoxyheterocyclyl, alkoxyheteroaryl,alkoxyacyl, alkoxyaralkyl, alkoxy, alkenyloxy, alkynyloxy, aryloxy,carbocyclyloxy, aralkyloxy, heteroaryloxy, heterocyclyloxy, acyloxy,haloalkoxy, haloalkenyloxy, haloalkynyloxy, haloaryloxy,halocarbocyclyloxy, haloaralkyloxy, haloheteroaryloxy,haloheterocyclyloxy, haloacyloxy, nitro, nitroalkyl, nitroalkenyl,nitroalkynyl, nitroaryl, nitroheterocyclyl, nitroheteroayl,nitrocarbocyclyl, nitroacyl, nitroaralkyl, amino (NH₂), alkylamino,dialkylamino, alkenylamino, alkynylamino, arylamino, diarylamino,aralkylamino, diaralkylamino, acylamino, diacylamino, heterocyclamino,heteroarylamino, carboxy, carboxyester, amido, alkylsulphonyloxy,arylsulphenyloxy, alkylsulphenyl, arylsulphenyl, thio, alkylthio,alkenylthio, alkynylthio, arylthio, aralkylthio, carbocyclylthio,heterocyclylthio, heteroarylthio, acylthio, sulfoxide, sulfonyl,sulfonamide, aminoalkyl, aminoalkenyl, aminoalkynyl, aminocarbocyclyl,aminoaryl, aminoheterocyclyl, aminoheteroaryl, aminoacyl, aminoaralkyl,thioalkyl, thioalkenyl, thioalkynyl, thiocarbocyclyl, thioaryl,thioheterocyclyl, thioheteroaryl, thioacyl, thioaralkyl, carboxyalkyl,carboxyalkenyl, carboxyalkynyl, carboxycarbocyclyl, carboxyaryl,carboxyheterocyclyl, carboxyheteroaryl, carboxyacyl, carboxyaralkyl,carboxyesteralkyl, carboxyesteralkenyl, carboxyesteralkynyl,carboxyestercarbocyclyl, carboxyesteraryl, carboxyesterheterocyclyl,carboxyesterheteroaryl, carboxyesteracyl, carboxyesteraralkyl,amidoalkyl, amidoalkenyl, amidoalkynyl, amidocarbocyclyl, amidoaryl,amidoheterocyclyl, amidoheteroaryl, amidoacyl, amidoaralkyl,formylalkyl, formylalkenyl, formylalkynyl, formylcarbocyclyl,formylaryl, formylheterocyclyl, formylheteroaryl, formylacyl,formylaralkyl, acylalkyl, acylalkenyl, acylalkynyl, acylcarbocyclyl,acylaryl, acylheterocyclyl, acylheteroaryl, acylacyl, acylaralkyl,sulfoxidealkyl, sulfoxidealkenyl, sulfoxidealkynyl,sulfoxidecarbocyclyl, sulfoxidearyl, sulfoxideheterocyclyl,sulfoxideheteroaryl, sulfoxideacyl, sulfoxidearalkyl, sulfonylalkyl,sulfonylalkenyl, sulfonylalkynyl, sulfonylcarbocyclyl, sulfonylaryl,sulfonylheterocyclyl, sulfonylheteroaryl, sulfonylacyl, sulfonylaralkyl,sulfonamidoalkyl, sulfonamidoalkenyl, sulfonamidoalkynyl,sulfonamidocarbocyclyl, sulfonamidoaryl, sulfonamidoheterocyclyl,sulfonamidoheteroaryl, sulfonamidoacyl, sulfonamidoaralkyl, nitroalkyl,nitroalkenyl, nitroalkynyl, nitrocarbocyclyl, nitroaryl,nitroheterocyclyl, nitroheteroaryl, nitroacyl, nitroaralkyl, cyano,sulfate and phosphate groups.

Preferred optional substituents include the aforementioned reactivefunctional groups or moieties, polymer chains and alkyl, (e.g. C₁₋₆alkyl such as methyl, ethyl, propyl, butyl, cyclopropyl, cyclobutyl,cyclopentyl or cyclohexyl), hydroxyalkyl (e.g. hydroxymethyl,hydroxyethyl, hydroxypropyl), alkoxyalkyl (e.g. methoxymethyl,methoxyethyl, methoxypropyl, ethoxymethyl, ethoxyethyl, ethoxypropyletc) alkoxy (e.g. C₁₋₆ alkoxy such as methoxy, ethoxy, propoxy, butoxy,cyclopropoxy, cyclobutoxy), halo, trifluoromethyl, trichloromethyl,tribromomethyl, hydroxy, phenyl (which itself may be further substitutede.g., by C₁₋₆ alkyl, halo, hydroxy, hydroxyC₁₋₆ alkyl, C₁₋₆ alkoxy,haloC₁₋₆alkyl, cyano, nitro OC(O)C₁₋₆ alkyl, and amino), benzyl (whereinbenzyl itself may be further substituted e.g., by C₁₋₆ alkyl, halo,hydroxy, hydroxyC₁₋₆alkyl, C₁₋₆ alkoxy, haloC₁₋₆ alkyl, cyano, nitroOC(O)C₁₋₆ alkyl, and amino), phenoxy (wherein phenyl itself may befurther substituted e.g., by C₁₋₆ alkyl, halo, hydroxy, hydroxyC₁₋₆alkyl, C₁₋₆ alkoxy, haloC₁₋₆ alkyl, cyano, nitro OC(O)C₁₋₆ alkyl, andamino), benzyloxy (wherein benzyl itself may be further substitutede.g., by C₁₋₆ alkyl, halo, hydroxy, hydroxyC₁₋₆ alkyl, C₁₋₆ alkoxy,haloC₁₋₆ alkyl, cyano, nitro OC(O)C₁₋₆ alkyl, and amino), amino,alkylamino (e.g. C₁₋₆ alkyl, such as methylamino, ethylamino,propylamino etc), dialkylamino (e.g. C₁₋₆ alkyl, such as dimethylamino,diethylamino, dipropylamino), acylamino (e.g. NHC(O)CH₃), phenylamino(wherein phenyl itself may be further substituted e.g., by C₁₋₆ alkyl,halo, hydroxy hydroxyC₁₋₆ alkyl, C₁₋₆ alkoxy, haloC₁₋₆ alkyl, cyano,nitro OC(O)C₁₋₆ alkyl, and amino), nitro, formyl, —C(O)-alkyl (e.g. C₁₋₆alkyl, such as acetyl), O—C(O)-alkyl (e.g. C₁₋₆alkyl, such asacetyloxy), benzoyl (wherein the phenyl group itself may be furthersubstituted e.g., by C₁₋₆ alkyl, halo, hydroxy hydroxyC₁₋₆ alkyl, C₁₋₆alkoxy, haloC₁₋₆ alkyl, cyano, nitro OC(O)C₁₋₆alkyl, and amino),replacement of CH₂ with C═O, CO₂H, CO₂alkyl (e.g. C₁₋₆ alkyl such asmethyl ester, ethyl ester, propyl ester, butyl ester), CO₂phenyl(wherein phenyl itself may be further substituted e.g., by C₁₋₆ alkyl,halo, hydroxy, hydroxyl C₁₋₆ alkyl, C₁₋₆ alkoxy, halo C₁₋₆ alkyl, cyano,nitro OC(O)C₁₋₆ alkyl, and amino), CONH₂, CONHphenyl (wherein phenylitself may be further substituted e.g., by C₁₋₆ alkyl, halo, hydroxy,hydroxyl C₁₋₆ alkyl, C₁₋₆ alkoxy, halo C₁₋₆ alkyl, cyano, nitroOC(O)C₁₋₆ alkyl, and amino), CONHbenzyl (wherein benzyl itself may befurther substituted e.g., by C₁₋₆ alkyl, halo, hydroxy hydroxyl C₁₋₆alkyl, C₁₋₆ alkoxy, halo C₁₋₆ alkyl, cyano, nitro OC(O)C₁₋₆ alkyl, andamino), CONHalkyl (e.g. C₁₋₆ alkyl such as methyl amide, ethyl amide,propyl amide, butyl amide) CONHdialkyl (e.g. C₁₋₆ alkyl) aminoalkyl(e.g., HN C₁₋₆ alkyl-, C₁₋₆alkylHN—C₁₋₆ alkyl- and (C₁₋₆ alkyl)₂N—C₁₋₆alkyl-), thioalkyl (e.g., HS C₁₋₆ alkyl-), carboxyalkyl (e.g., HO₂CC₁₋₆alkyl-), carboxyesteralkyl (e.g., C₁₋₆ alkylO₂CC₁₋₆ alkyl-), amidoalkyl(e.g., H₂N(O)CC₁₋₆ alkyl-, H(C₁₋₆ alkyl)N(O)CC₁₋₆ alkyl-), formylalkyl(e.g., OHCC₁₋₆alkyl-), acylalkyl (e.g., C₁₋₆ alkyl(O)CC₁₋₆ alkyl-),nitroalkyl (e.g., O₂NC₁₋₆ alkyl-), sulfoxidealkyl (e.g., R³(O)SC₁₋₆alkyl, such as C₁₋₆ alkyl(O)SC₁₋₆ alkyl-), sulfonylalkyl (e.g.,R³(O)₂SC₁₋₆ alkyl- such as C₁₋₆ alkyl(O)₂SC₁₋₆ alkyl-), sulfonamidoalkyl(e.g., 2HRN(O)SC₁₋₆ alkyl, H(C₁₋₆ alkyl)N(O)SC₁₋₆ alkyl-).

It is understood that the compounds of the present invention (includingmonomers and polymers) may exist in one or more stereoisomeric forms (egenantiomers, diastereomers). The present invention includes within itsscope all of these stereoisomeric forms either isolated (in for exampleenantiomeric isolation), or in combination (including racemic mixtures).

The following examples are intended to illustrate the scope of theinvention and to enable reproduction and comparison. They are notintended to limit the scope of the disclosure in any way.

EXAMPLES General Experimental Procedures Monomer Synthesis

Method 1a: Carbodiimide Mediated Ester Formation.

To a solution of the carboxylic acid substrate (≧1.5 mol eq. to thehydroxyl group), the alcohol derivative (1.0 eq) and DMAP (0.1 mol. eq.of the carboxylic acid group) in anhydrous DCM,N,N′-dicyclohexylcarbodiimide (DCC) (1 mol. eq. to the carboxylic acidgroup) is added at 0° C. The mixture is stirred at room temperature for16 h or until the reaction is complete. The reaction mixture is filteredthrough a thin bed of Celite, concentrated and dried in vacuo. Columnchromatography is used to isolate the pure product.

Method 1b: Carbodiimide Mediated Ester Formation. Acid Preactivation.

A solution of alcohol (1.0 eq.) in anhydrous DCM is added dropwise to asolution of the carboxylic acid substrate (˜1.0 eq.), DCC (˜1.0 eq.) andDMAP (0.1 eq.) in anhydrous DCM at 0° C. The mixture is stirred at roomtemperature for 16 h or until the reaction is complete. The reactionmixture is filtered through a thin bed of celite, concentrated and driedin vacuo.

Method 2: HBTU Mediated Ester Formation

A solution of the carboxylic acid substrate (1.0 eq.) in anhydrous THFis added dropwise into a stirring solution of HBTU (˜1.2 eq.), thealcohol derivative (˜1.6 eq.) and triethylamine (˜4.3 eq.) in anhydrousTHF under nitrogen atmosphere. The mixture is stirred at roomtemperature for 3 days, with the exclusion of light, or until thereaction is complete. The reaction is quenched with 1M aqueous citricacid and extracted with ethyl acetate. The organic phase is then washedwith saturated aqueous sodium hydrogen carbonate, followed by brine. Theorganic phase is then dried over Na₂SO₄, filtered, concentrated anddried in vacuo.

Method 3: BOP-Cl Mediated Ester Formation

To a stirred solution of the alcohol derivative (1.0 eq.), thecarboxylic acid substrate (1.0 eq.) and triethylamine (2.0 eq.) inanhydrous DCM, BOP-Cl (1.0 eq.) is added. The reaction mixture isstirred at room temperature for 16 h or until the reaction is complete.The reaction mixture is washed with saturated aqueous sodium hydrogencarbonate, water, and brine. The organic phase is then dried overNa₂SO₄, filtered, concentrated and dried in vacuo.

Method 4: Formation of Chloroformate

To a solution of the alcohol derivative (1.0 eq) and triphosgene (0.5eq.) in anhydrous DCM, pyridine (1.3 eq) is added dropwise at −40° C.The reaction mixture is stirred at −40° C. for 2 h, then slowly warm toroom temperature and stirred for 4 h or until the reaction is complete.The reaction mixture is filtered through a thin layer of silica gel,concentrated and dried in vacuo.

Method 5: Carbonate Formation

To a solution of requisite alcohol (1.0 eq) in anhydrous pyridine,chloroformate derivative (2-3 eq) is added at 0° C. The reaction mixtureis stirred at room temperature for 16 h or until the reaction iscomplete. The residue is to extract in ethyl acetate and washed withwater and brine. The organic phase is dried over Na₂SO₄, filtered,concentrated and dried in vacuo.

Preparation of Monomer-Bioactive Agent Conjugates Precursors Example 1:2-(Prop-2-yn-1-yl)pent-4-yn-1-ol

Prepared following the procedure of Carney et al. Org. Lett. 2008, 10,3903.

Example 2: 2-Hydroxypropane-1,3-diyl bis(hex-5-ynoate)

5-Hexynoic acid (3.2 mL, 3.25 g 28.9 mmol), dihydroxyacetone dimer(1.0238 g, 5.68 mmol), DMAP (0.0348 g, 0.28 mmol) and DCC (4.7382 g,22.9 mmol) in anhydrous DCM (50 mL) were reacted according to Method 1aoutlined above. The crude residue was purified on a thin bed of silicagel, using 50% EtOAc in pet. spirit as eluent to give2-oxopropane-1,3-diyl bis(hex-5-ynoate) as a white solid (quantitativeyield). ¹H NMR (400 MHz, CDCl₃) δ 4.76 (s, 4H), 2.58 (t, J=7.4 Hz, 4H),2.29 (td, J=6.9, 2.7 Hz, 4H), 1.98 (t, J=2.7 Hz, 2H), 1.88 (p, J=7.1 Hz,4H).

To a solution of 2-oxopropane-1,3-diyl bis(hex-5-ynoate) (376 mg, 1.35mmol) in anhydrous THF (10 mL), sodium cyanoborohydride (94 mg, 1.51mmol) was added. Glacial acetic acid was immediately added dropwiseuntil the solution was at pH 4. The reaction mixture was stirred at roomtemperature for 30 mins. The mixture was quenched with water andextracted with DCM. The organic phase was dried over anhydrous Na₂SO₄,filtered, concentrated and dried in vacuo to give the title compound asa clear colourless oil (338.5 mg, 89% yield). ¹H NMR (400 MHz, CDCl₃) δ4.20-3.99 (m, 5H), 2.45 (t, J=7.4 Hz, 4H), 2.21 (td, J=6.9, 2.7 Hz, 4H),1.92 (t, J=2.7 Hz, 2H), 1.79 (p, J=7.1 Hz, 4H). ¹³C NMR (101 MHz, CDCl₃)δ 173.12, 83.07, 69.34, 68.20, 65.14, 32.64, 23.45, 17.77.

Example 3: 2-(Prop-2-yn-1-yl)pent-4-yn-1-yl 4-hydroxybenzoate

To a solution of 2-(prop-2-yn-1-yl)pent-4-yn-1-ol (J. Org. Chem. 2002,67, 2778) (380 mg, 3.11 mmol), 4-acetoxybenzoic acid (619 mg, 3.43 mmol)and DMAP (36.9 mg, 0.30 mmol) in DCM at 0° C. was added EDC-HCl (663 mg,3.46 mmol) and the resulting solution stirred at 0° C. for 1 h beforeallowing to warm to rt. The mixture was stirred for an additional 21 hbefore further EDC-HCl (652 mg, 3.40 mmol) was added. The resultantmixture was stirred at rt for an additional 24 h before Et₂O and H₂Owere added. The product was extracted (Et₂O), washed (H₂O, then brine),dried (Na₂SO₄), filtered and concentrated under reduced pressure. Flashchromatography (0-100% EtOAc/petrol gradient elution) gave2-(prop-2-yn-1-yl)pent-4-yn-1-yl 4-acetoxybenzoate (427 mg, 1.50 mmol,48%) as a colourless oil. 2-(prop-2-yn-1-yl)pent-4-yn-1-yl4-acetoxybenzoate (423.3 mg, 1.49 mmol) was dissolved in a 3:1 mixtureof MeOH:H₂O (16 mL) before NH₄OAc (583.6 mg, 7.57 mmol) was added. Theresultant mixture was stirred at rt for 76 h before EtOAc and H₂O wereadded. The product was extracted (EtOAc), washed (H₂O, then brine),dried (Na₂SO₄), filtered and concentrated under reduced pressure. Flashchromatography (0-100% EtOAc/petrol gradient elution) gave the titlecompound (295.1 mg, 1.22 mmol, 82%) as a white solid. ESI-MS: m/z 243([M+H]⁺). ¹H NMR (400 MHz CDCl₃): δ 7.95 (m, 2H), 6.86 (m, 2H), 4.38 (d,J=6.1 Hz, 2H), 2.47 (dd, J=6.2, 2.7 Hz, 4H), 2.28 (m, 1H), 2.03 (t,J=2.7 Hz, 2H).

Example 4: 4-Hydroxy-N-(2-(prop-2-yn-1-yl)pent-4-yn-1-yl)benzamide

In a similar manner to Example 3: 2-(Prop-2-yn-1-yl)pent-4-yn-1-yl4-hydroxybenzoate described above 2-(prop-2-yn-1-yl)pent-4-yn-1-aminemay be reacted with 4-acetoxybenzoic acid followed by NH₄.OAc mediateddeacetylation to give the title compound.

Example 5: (5-Hydroxy-6-methylpyridine-3,4-diyl)bis(methylene)bis(hex-5-ynoate)

NaH (60% dispersion in mineral oil, 1.10 g, 27.5 mmol) was washed withdry petroleum spirit and dried under N₂. The solid was then suspended inDMF (100 mL) and cooled to 0° C. before pyridoxine.HCl (2.50 g, 12.2mmol) was added and the mixture stirred at 0° C. for 30 min, beforeallowing to warm to rt for 15 min. The mixture was recooled to 0° C. andPMBCl (1.84 mL, 13.6 mmol) was added and the resulting mixture allowedto gradually warm to rt over 42 h. MeOH was added to quench before thesolvent was removed under reduced pressure. Flash chromatography (0-30%MeOH/DCM gradient elution) gave(5-((4-methoxybenzyl)oxy)-6-methylpyridine-3,4-diyl)dimethanol (920 mg,3.18 mmol, 26%) as a yellow-orange solid.(5-((4-Methoxybenzyl)oxy)-6-methylpyridine-3,4-diyl)dimethanol (166 mg,0.574 mmol), 5-hexynoic acid (160 μL, 1.45 mmol), DCC (284.3 mg, 1.38mmol) and DMAP (10.5 mg, 0.085 mmol) in DCM were reacted for 4 haccording to the procedure outlined in Method 1a, above. Flashchromatography (0-100% EtOAc/petrol gradient elution) gave(5-((4-methoxybenzyl)oxy)-6-methylpyridine-3,4-diyl)bis(methylene)bis(hex-5-ynoate) (236.2 mg, 0.495 mmol, 86%) as a colourlesscrystalline solid. To a solution of(5-((4-methoxybenzyl)oxy)-6-methylpyridine-3,4-diyl)bis(methylene)bis(hex-5-ynoate) (110.9 mg, 0.232 mmol) in DCM was added Et₃SiH (39 μL,0.244 mmol) and the resulting mixture stirred at rt for 10 min.Trifluoroacetic acid (100 μL, 1.31 mmol) was added and the mixturestirred for a further 19 h before the solvent was removed under reducedpressure. Flash chromatography (0-30% MeOH/DCM gradient elution) yieldedthe title compound (83.1 mg, 0.232 mmol, quant.). ESI-MS: m/z 358([M+H]⁺). ¹H NMR (400 MHz): δ 8.32 (s, 1H), 5.29 (s, 2H), 5.26 (s, 2H),2.69 (s, 3H), 2.56 (dt, J=11.5, 7.4 Hz, 4H), 2.27 (ddd, J=11.9, 6.9, 2.6Hz, 4H), 1.99 (t, J=2.6 Hz, 1H), 1.96 (t, J=2.6 Hz, 1H), 1.86 (m, 4H).¹³C NMR (100 MHz): δ 175.9, 172.6, 152.4, 148.1, 135.4, 132.6, 132.5,83.0, 82.7, 69.9, 69.7, 60.5, 57.6, 32.7, 32.5, 23.4, 23.3, 17.9, 17.8,16.6.

Example 6: 2-(Prop-2-yn-1-yl)pent-4-ynoic acid

2M NaOH (2.6 mL, 5.2 mmol) was added to methyl2-(prop-2-yn-1-yl)pent-4-ynoate (Org. Lett. 2008, 10(17), 3903) (383 mg,2.55 mmol) before EtOH (19 mL) was added and the resulting solutionheated to reflux for 22 h. The mixture was allowed to cool to rt andstirred for a further 42 h before the EtOH was removed under reducedpressure. The crude mixture was then diluted (Et₂O and H₂O) and the Et₂Ofraction was extracted with H₂O before discarding. The aqueous fractionswere combined and acidified with 2M HCl to pH˜1 before the product wasextracted with Et₂O. The organic fractions were dried (Na₂SO₄), filteredand concentrated under reduced pressure to provide the title compound(330 mg, 2.42 mmol, 95%) as a colourless solid which was used withoutfurther purification. ¹H NMR (400 MHz CDCl₃): δ 2.83 (m, 1H), 2.68 (m,4H), 2.05 (t, J=2.6 Hz, 2H). ¹³C NMR (100 MHz): δ 177.7, 80.2, 71.0,42.9, 19.8.

Example 7:3-(Hex-5-ynoyloxy)-2-((hex-5-ynoyloxy)methyl)-2-methylpropanoic acid

5-Hexynoic acid (5.01 g, 44.9 mmol) was dissolved in DMF (42 mL) andcooled to 0° C. Oxalyl chloride (3.3 mL, 38.5 mmol) was added dropwise(gas evolution) and the resulting mixture stirred at 0° C. for 40 min.The solution was then added via cannula to a chilled (0° C.) solution of2,2-dihydroxymethyl-propanoic acid (1.51 g, 11.3 mmol), NEt₃ (23.4 mL,169 mmol) and DMAP (693 mg, 5.67 mmol) in DMF (50 mL) and the resultingmixture allowed to gradually warm to rt and stirred for 74 h. Themixture was acidified using 1M HCl to pH˜2, before the product wasextracted (EtOAc), washed (H₂O, then brine), dried (Na₂SO₄), filteredand concentrated under reduced pressure. Flash chromatography (20-60%EtOAc/petrol gradient elution) gave 4.6 g of a mixture of product andimpurity, which was resubjected to flash chromatography (20-100%EtOAc/petrol gradient elution) to give the title compound as acolourless oil (3.11 g, 9.65 mmol, 85%). ESI-MS: m/z 345 ([M+Na]⁺). ¹HNMR (400 MHz CDCl₃): δ 1.30 (s, 3H), 1.84 (p, J=7.1 Hz, 4H), 1.98 (t,J=2.7 Hz, 2H), 2.26 (td, J=6.9, 2.6 Hz, 4H), 2.48 (t, J=7.4 Hz, 4H),4.24 (d, J=11.1 Hz, 2H), 4.28 (d, J=11.1 Hz, 2H). ¹³C NMR (100 MHz): δ178.2, 172.7, 83.2, 69.5, 65.2, 46.2, 32.8, 23.6, 17.93, 17.90.

Example 8: 1,3-Bis(prop-2-yn-1-yloxy)propan-2-ol

1,3-Dihydroxypropan-2-yl acetate (0.700 g, 5.22 mmol) was reacted withpropargyl bromide (2.48 g, 20.9 mmol) in the presence of sodium hydride(0.835 g, 37.2 mmol) in 15 mL of anhydrous THF for 72 hours to give1,3-bis(prop-2-yn-1-yloxy)propan-2-yl acetate. Saponification with LiOH(1 eq) in MeOH:THF:Water (3:1:1) is followed by acidification withcitric acid and extraction into ethyl acetate. The organic phase isdried, filtered and the solvent removed to give the title compound.

Example 9: (Z)-Isopropyl7-((1R,5S,6R,7R)-3-butyl-7-((R)-3-hydroxy-5-phenylpentyl)-2,4-dioxa-3-borabicyclo[3.2.1]octan-6-yl)hept-5-enoate

To latanoprost (222.0 mg, 0.51 mmol) in anhydrous DCM (10 mL) was addedn-butylboronic acid (60.1 mg, 0.59 mmol). The mixture was heated at 45°C. for 1 h under nitrogen atmosphere. Solvent was then removed and driedin vacuo for 2 h. Additional anhydrous DCM was added and dried in vacuofor further 3 h. The residue was again heated in anhydrous DCM (10 mL)at 45° C. for 16 h. Solvent was removed under reduced pressure,obtaining a clear colourless oil and used directly in the next stepwithout further purification. ¹H NMR (400 MHz, CDCl₃) δ (ppm): 7.28-7.17(m, 2H), 7.17-7.03 (m, 3H), 5.49-5.27 (m, 2H), 4.93 (ddd, J=15.2, 7.6,4.9 Hz, 1H), 4.28-4.13 (m, 1H), 4.07-3.90 (m, 1H), 3.65-3.46 (m, 1H),2.78-2.67 (m, 1H), 2.67-2.41 (m, 1H), 2.28-2.11 (m, 4H), 2.09-1.98 (m,2H), 1.91-1.79 (m, 1H), 1.79-1.53 (m, 7H), 1.53-1.38 (m, 3H), 1.38-1.07(m, 12H), 0.89-0.75 (m, 3H), 0.64-0.52 (m, 2H).

Also made using the same method are Examples 10 and 11:

Example 10:(Z)-7-((1R,5S,6R,7R)-3-Butyl-7-((R)-3-hydroxy-5-phenylpentyl)-2,4-dioxa-3-borabicyclo[3.2.1]octan-6-yl)hept-5-enoicacid

¹H NMR (400 MHz, CDCl₃) δ 7.33-7.25 (m, 2H), 7.23-7.10 (m, 3H),5.62-5.44 (m, 1H), 5.44-5.34 (m, 1H), 4.31 (s, 1H), 4.04 (s, 1H), 3.73(s, 1H), 2.89-2.47 (m, 2H), 2.47-1.99 (m, 6H), 1.99-1.87 (m, 1H),1.87-1.07 (m, 15H), 0.93-0.82 (m, 4H), 0.82-0.71 (m, 1H), 0.71-0.52 (m,2H).

Example 11: (Z)-Isopropyl7-((1R,5S,6R,7R)-3-butyl-7-((R,E)-3-hydroxy-4-(3-(trifluoromethyl)phenoxy)but-1-en-1-yl)-2,4-dioxa-3-borabicyclo[3.2.1]octan-6-yl)hept-5-enoate

¹H NMR (400 MHz, CDCl₃) δ 7.44-7.35 (m, 1H), 7.30-7.19 (m, 1H),7.17-7.11 (m, 1H), 7.11-7.03 (m, 1H), 5.77-5.66 (m, 1H), 5.66-5.56 (m,1H), 5.52-5.30 (m, 2H), 5.09-4.90 (m, 1H), 4.60-4.44 (m, 1H), 4.34 (s,1H), 4.20-4.10 (m, 1H), 4.06-3.77 (m, 2H), 2.53-2.37 (m, 1H), 2.34-2.20(m, 4H), 2.16-2.04 (m, 2H), 2.03-1.93 (m, 1H), 1.92-1.73 (m, 2H),1.73-1.59 (m, 2H), 1.43-1.24 (m, 6H), 1.23 (s, 3H), 1.21 (s, 3H),0.95-0.83 (m, 4H), 0.72-0.55 (m, 2H).

Example 12: (Z)-2-(Prop-2-yn-1-yl)pent-4-yn-1-yl7-((1R,2R,3R,5S)-3,5-dihydroxy-2-((R)-3-hydroxy-5-phenylpentyl)cyclopentyl)hept-5-enoate

A solution of latanoprost free acid (0.3989 g, 1.02 mmol) in anhydrousDCM (10 mL) was added dropwise into a solution mixture of2-(prop-2-yn-1-yl)pent-4-yn-1-ol (0.1405 g, 1.15 mmol), HBTU (0.4391 g,1.16 mmol) and triethylamine (0.60 mL, 0.4362 g, 4.31 mmol) in anhydrousDCM (5 mL) according to the procedure outlined in Method 2 above. Thecrude residue was purified on the automated flash chromatography using0%-20% MeOH in DCM gradient elution to give the title compound as aclear colourless viscous oil (0.2251 g, 45% yield). ESI-MS: m/z 540([M+2Na]⁺). ¹H NMR (400 MHz, CDCl₃) δ 7.33-7.24 (m, 2H), 7.24-7.14 (m,3H), 5.56-5.32 (m, 2H), 4.23-4.06 (m, 3H), 4.01-3.88 (m, 1H), 3.73-3.60(m, 1H), 2.88-2.58 (m, 3H), 2.44-2.27 (m, 8H), 2.25-2.05 (m, 4H), 2.01(t, J=2.7 Hz, 2H), 1.90-1.84 (m, 2H), 1.84-1.46 (m, 9H), 1.46-1.18 (m,2H). ¹³C NMR (101 MHz, CDCl₃) δ 173.79, 142.20, 129.63, 129.57, 128.56,128.55, 125.98, 81.04, 78.94, 74.88, 71.45, 70.63, 65.28, 53.06, 52.03,42.68, 39.22, 36.38, 35.94, 33.70, 32.26, 29.79, 27.09, 26.76, 24.96,20.00.

Example 13:2-(((Z)-7-((1R,2R,3R,5S)-3,5-Dihydroxy-2-((R)-3-hydroxy-5-phenylpentyl)cyclopentyl)hept-5-enoyl)oxy)propane-1,3-diylbis(hex-5-ynoate)

A solution of latanoprost free acid (0.1940 g, 0.50 mmol) in anhydrousDCM (10 mL) was added dropwise into a solution mixture of2-hydroxypropane-1,3-diyl bis(hex-5-ynoate) (0.1800 g, 0.64 mmol), HBTU(0.2109 g, 0.56 mmol) and triethylamine (0.3 mL, 0.2181 g, 2.20 mmol) inanhydrous DCM (5 mL) according to the procedure outlined in Method 2above. The crude residue was purified on the automated flashchromatography using 0%-30% MeOH in DCM gradient elution to give thetitle compound as a clear colourless oil (0.1346 g, 42% yield). ESI-MS:m/z 698 ([M+2Na]⁺). ¹H NMR (400 MHz, CDCl₃) δ 7.35-7.24 (m, 2H),7.24-7.12 (m, 3H), 5.53-5.32 (m, 2H), 5.32-5.16 (m, 1H), 4.37-4.23 (m,2H), 4.23-4.08 (m, 3H), 3.93 (t, J=8.6 Hz, 1H), 3.67 (m, 1H), 2.86-2.74(m, 1H), 2.74-2.59 (m, 2H), 2.47 (tt, J=7.4, 3.7 Hz, 4H), 2.43-2.03 (m,12H), 1.98 (t, J=2.6 Hz, 2H), 1.91-1.45 (m, 13H), 1.45-1.17 (m, 3H). ¹³CNMR (101 MHz, CDCl₃) δ 173.33, 172.66, 172.27, 142.12, 129.62, 129.27,128.42, 125.83, 83.08, 78.72, 74.62, 71.28, 69.40, 69.38, 69.08, 68.94,62.26, 62.18, 52.81, 51.81, 42.56, 39.07, 35.78, 33.53, 33.38, 32.78,32.60, 32.12, 29.62, 26.93, 26.56, 26.53, 24.77, 24.73, 23.50, 23.44,17.77, 17.74.

Example 14: 2-(Prop-2-yn-1-yl)pent-4-yn-1-yl4-(((Z)-7-((1R,2R,3R,5S)-3,5-dihydroxy-2-((R)-3-hydroxy-5-phenylpentyl)cyclopentyl)hept-5-enoyl)oxy)benzoate

A solution of latanoprost free acid (102.4 mg, 0.26 mmol) in DCM (5 mL)was added dropwise to a solution of 2-(prop-2-yn-1-yl)pent-4-yn-1-yl4-hydroxybenzoate (124.4 mg, 0.51 mmol), HBTU (111.1 mg, 0.29 mmol) andNEt₃ (214 μL, 1.54 mmol) in DCM (2 mL) according to the procedureoutlined in Method 2. Flash chromatography (0-30% MeOH/DCM gradientelution) gave the title compound (57.7 mg, 0.094 mmol, 36%) as acolourless viscous oil. ESI-MS: m/z 615 ([M+H]⁺). ¹H NMR (400 MHzCDCl₃): δ 8.06 (m, 2H), 7.28 (m, 2H), 7.20-7.15 (m, 5H), 5.48 (m, 2H),4.40 (d, J=6.1 Hz, 2H), 4.17 (s, 1H), 3.96 (s, 1H), 3.65 (m, 1H), 2.78(ddd, J=13.5, 9.1, 6.3 Hz, 1H), 2.67 (m, 1H), 2.60 (t, J=7.3 Hz, 2H),2.47 (dd, J=6.5, 2.6 Hz, 4H), 2.41-2.21 (m, 5H), 2.03 (t, J=2.6 Hz, 2H),1.88-1.67 (m, 7H), 1.64-1.48 (m, 3H), 1.44-1.31 (m, 2H). ¹³C NMR (100MHz): δ 171.9, 165.7, 154.6, 142.1, 131.4, 129.9, 129.4, 128.6, 128.5,127.7, 126.0, 121.8, 81.0, 79.0, 75.0, 71.5, 70.7, 66.0, 53.1, 52.1,42.7, 39.2, 36.6, 35.9, 33.9, 32.3, 29.8, 27.2, 26.7, 24.8, 20.2.

Example 15:(5-(((Z)-7-((1R,2R,3R,5S)-3,5-Dihydroxy-2-((R)-3-hydroxy-5-phenylpentyl)cyclopentyl)hept-5-enoyl)oxy)-6-methylpyridine-3,4-diyl)bis(methylene)bis(hex-5-ynoate)

Latanoprost free acid (61.6 mg, 0.158 mmol),(5-hydroxy-6-methylpyridine-3,4-diyl)bis(methylene) bis(hex-5-ynoate)(82.1 mg, 0.230 mmol), HBTU (72.0 mg, 0.190 mmol), NEt₃ (128 μL, 0.923mmol) and DCM (5 mL) were reacted according to the procedure outlined inMethod 2. The crude material was purified by flash chromatography (0-30%MeOH/DCM gradient elution) to provide the title compound (74.8 mg, 0.102mmol, 65%) as a colourless viscous oil. ESI-MS: m/z 730 ([M+H]⁺). ¹H NMR(400 MHz CDCl₃): δ 8.45 (s, 1H), 7.28 (m, 2H), 7.20-7.16 (m, 3H), 5.48(m, 2H), 5.28 (s, 2H), 5.13 (s, 2H), 4.18 (s, 1H), 3.96 (m, 1H), 3.66(m, 1H), 2.79 (ddd, J=13.6, 9.0, 6.3 Hz, 1H), 2.70-2.63 (m, 3H), 2.48(t, J=7.4 Hz, 2H), 2.44-2.34 (m, 6H), 2.27-2.21 (m, 7H), 1.96 (t, J=2.6Hz, 2H), 1.89-1.49 (m, 14H), 1.45-1.30 (m, 2H). ¹³C NMR (100 MHz): δ172.7, 172.6, 171.4, 152.9, 147.1, 145.0, 142.2, 136.4, 130.1, 129.1,128.6, 128.5, 126.0, 83.14, 83.13, 78.9, 74.9, 71.4, 69.6, 61.2, 57.0,53.1, 52.0, 42.8, 39.3, 35.9, 33.5, 32.8, 32.6, 32.3, 29.8, 27.2, 26.8,24.8, 23.51, 23.47, 19.5, 17.91, 17.88.

Example 16:2-((((Z)-7-((1R,2R,3R,5S)-3,5-Dihydroxy-2-((R)-3-hydroxy-5-phenylpentyl)cyclopentyl)hept-5-enoyl)oxy)methyl)-2-methylpropane-1,3-diylbis(hex-5-ynoate)

A solution of 5-hexynoic acid (35 μL, 35.56 mg, 0.32 mmol), HBTU (83.3mg, 0.22 mmol) and triethylamine (87 μL, 119.7 mg, 0.63 mmol) inanhydrous DCM (2 mL) was stirred at room temperature for ˜1 hr or untilHBTU was dissolved. The mixture was then added dropwise to a solution of(Z)-3-hydroxy-2-(hydroxymethyl)-2-methylpropyl7-((1R,2R,3R,5S)-3,5-dihydroxy-2-((R)-3-hydroxy-5-phenylpentyl)cyclopentyl)hept-5-enoate(WO 2012/139164) (76.6 mg, 0.16 mmol) in anhydrous DCM (3 mL). Themixture was stirred at room temperature with the exclusion of light.After 4 days, a solution of 5-hexynoic acid (35 μL, 35.56 mg, 0.32mmol), HBTU (83.7 mg, 0.22 mmol), triethylamine (87 μL, 119.7 mg, 0.63mmol) in anhydrous DCM (2 mL) was added and stirred for further 3 days.The reaction was quenched with 1M aqueous citric acid and extracted withethyl acetate. The organic phase was then washed with saturated aqueoussodium hydrogen carbonate, followed by brine. The organic phase was thendried over Na₂SO₄, filtered, concentrated and dried in vacuo. The cruderesidue was purified (SiO₂, MeOH:CHCl₃, 2:98). The title compound wasobtained as a clear colourless oil (15.7 mg, 15% yield). ESI-MS: m/z 703([M+2Na]⁺). ¹H NMR (400 MHz, CDCl₃) δ 7.32-7.25 (m, 2H), 7.23-7.10 (m,3H), 5.57-5.27 (m, 2H), 4.16 (bs, 1H), 4.08-3.88 (m, 7H), 3.71-3.61 (m,1H), 2.87-2.73 (m, 1H), 2.73-2.58 (m, 1H), 2.51-2.42 (m, 4H), 2.40-2.03(m, 12H), 1.98 (t, J=2.6 Hz, 2H), 1.91-1.46 (m, 12H), 1.46-1.23 (m, 2H),1.02 (s, 3H). ¹³C NMR (101 MHz, CDCl₃) δ 173.63, 172.98, 142.20, 129.70,129.44, 128.54, 128.53, 125.97, 83.16, 78.92, 74.84, 71.41, 69.50,65.88, 65.81, 53.05, 51.99, 42.68, 39.22, 38.47, 35.93, 33.68, 32.83,32.25, 29.78, 27.09, 26.75, 24.93, 23.58, 17.91, 17.26.

Example 17: (Z)-Isopropyl7-((1R,2R,3R,5S)-3,5-dihydroxy-2-((R)-5-phenyl-3-((2-(prop-2-yn-1-yl)pent-4-ynoyl)oxy)pentyl)cyclopentyl)hept-5-enoate

A solution of example 9 (114.0 mg, 0.23 mmol) in anhydrous DCM (3 mL)was added dropwise to a solution of 2-(prop-2-yn-1-yl)pent-4-ynoic acid(33.9 mg, 0.25 mmol), DCC (52.9 mg, 0.26 mmol) and DMAP (8.4 mg, 0.07mmol) in anhydrous DCM (4 mL) according to Method 1b outlined above. Theresidue was dissolved in methanol (6 mL) and stirred at room temperaturefor 2 days. The crude residue was purified on the automated flashchromatography using 0%-100% EtOAc in pet. spirit gradient elution togive the title compound as a clear colourless oil (56.8 mg, 45% yield).ESI-MS: m/z 573 ([M+Na]⁺). ¹H NMR (400 MHz, CDCl₃) δ 7.37-7.25 (m, 2H),7.25-7.09 (m, 3H), 5.54-5.32 (m, 2H), 5.13-4.90 (m, 2H), 4.28-4.15 (m,1H), 3.97-3.83 (m, 1H), 2.84-2.58 (m, 8H), 2.41-2.26 (m, 3H), 2.25-2.09(m, 4H), 2.05 (t, J=2.6 Hz, 2H), 2.00-1.61 (m, 10H), 1.53-1.27 (m, 3H),1.25 (s, 3H), 1.24 (s, 3H). ¹³C NMR (101 MHz, CDCl₃) δ 173.48, 172.09,141.54, 129.80, 129.19, 128.45, 128.36, 125.98, 78.87, 74.78, 74.71,70.73, 70.72, 67.68, 52.98, 51.71, 43.30, 42.49, 36.00, 34.04, 32.95,31.69, 29.43, 26.91, 26.68, 24.92, 21.86, 20.06, 20.02.

Example 18:2-((((R)-1-((1R,2R,3S,5R)-3,5-Dihydroxy-2-((Z)-7-isopropoxy-7-oxohept-2-en-1-yl)cyclopentyl)-5-phenylpentan-3-yl)oxy)carbonyl)-2-methylpropane-1,3-diylbis(hex-5-ynoate)

A solution of example 9 (207.2 mg, 0.42 mmol) in anhydrous DCM (3 mL)was added dropwise to a solution of3-(hex-5-ynoyloxy)-2-((hex-5-ynoyloxy)methyl)-2-methylpropanoic acid(143.0 mg, 0.44 mmol), DCC (99.3 mg, 0.48 mmol) and DMAP (15.2 mg, 0.12mmol) in anhydrous DCM (5 mL) according to Method 1b outlined above. Theresidue was dissolved in methanol (6 mL) and stirred at room temperaturefor 24 hrs. The crude residue was purified on the automated flashchromatography using 0%-100% EtOAc in pet. spirit gradient elution togive the title compound as a clear colourless oil (104.2 mg, 42% yield).¹H NMR (400 MHz, CDCl₃) δ 7.34-7.26 (m, 2H), 7.23-7.10 (m, 3H),5.47-5.32 (m, 2H), 5.05-4.93 (m, 2H), 4.34-4.19 (m, 4H), 4.16 (bs, 1H),3.88 (bs, 1H), 2.71-2.50 (m, 2H), 2.48-2.39 (m, 4H), 2.39-2.25 (m, 5H),2.24-2.18 (m, 4H), 2.18-2.01 (m, 3H), 1.96-1.60 (m, 15H), 1.49-1.29 (m,4H), 1.26 (s, 3H), 1.23 (s, 3H), 1.21 (s, 3H). ¹³C NMR (101 MHz, CDCl₃)δ 173.56, 172.65, 172.58, 141.34, 129.99, 129.24, 128.65, 128.40,126.22, 83.18, 78.94, 74.94, 74.74, 69.46, 67.79, 65.52, 53.00, 51.79,46.49, 42.66, 36.01, 34.15, 32.87, 32.79, 32.77, 31.70, 29.51, 27.01,26.79, 25.03, 23.55, 23.53, 21.98, 18.16, 17.87.

Example 19:(R)-1-((1R,2R,3S,5R)-3,5-Dihydroxy-2-((Z)-7-isopropoxy-7-oxohept-2-en-1-yl)cyclopentyl)-5-phenylpentan-3-yl(2-(prop-2-yn-1-yl)pent-4-yn-1-yl) succinate

2-(Prop-2-yn-1-yl)pent-4-yn-1-ol (552.3 mg, 4.52 mmol) in anhydrous DCM(20 mL) was added succinic anhydride (5.99 mg, 5.99 mmol), DMAP (23.0mg, 0.19 mmol) and pyridine (0.36 mL, 28.0 mmol). The mixture was heatedat 45° C. for 16 h. The reaction mixture was washed with 1M HCl,followed by brine. The organic phase is then dried over Na₂SO₄,filtered, concentrated and dried in vacuo to give4-oxo-4-((2-(prop-2-yn-1-yl)pent-4-yn-1-yl)oxy)butanoic acid as a clearcolourless oil (quantitative yield). A solution of example 9 (117.7 mg,0.24 mmol) in anhydrous DCM (1 mL) was added dropwise to a solution of4-oxo-4-((2-(prop-2-yn-1-yl)pent-4-yn-1-yl)oxy)butanoic acid (60.6 mg,0.27 mmol), DCC (62.2 mg, 0.30 mmol) and DMAP (3.8 mg, 0.03 mmol) inanhydrous DCM (5 mL) according to Method 1b outlined above. The residuewas dissolved in methanol (2 mL) and stirred at room temperature for 3days. The crude residue was purified on the automated flashchromatography using 0%-100% EtOAc in pet. spirit gradient elution togive the title compound as a clear colourless oil (81.9 mg, 54% yield)¹HNMR (400 MHz, CDCl₃) δ 7.24-7.17 (m, 2H), 7.14-7.07 (m, 3H), 5.43-5.25(m, 2H), 4.97-4.83 (m, 2H), 4.15-4.03 (m, 3H), 3.83 (s, 1H), 2.67-2.43(m, 7H), 2.35-2.17 (m, 7H), 2.15-1.96 (m, 4H), 1.95 (t, J=2.6 Hz, 2H),1.91-1.75 (m, 4H), 1.75-1.50 (m, 6H), 1.43-1.23 (m, 3H), 1.16 (s, 3H),1.15 (s, 3H). ¹³C NMR (101 MHz, CDCl₃) δ 173.48, 172.18, 172.05, 141.56,129.62, 129.37, 128.44, 128.37, 125.95, 78.69, 74.60, 74.47, 70.58,67.65, 65.48, 52.80, 51.63, 42.50, 36.26, 35.85, 34.09, 32.76, 31.76,29.32, 29.27, 29.07, 26.95, 26.68, 24.96, 21.88, 19.85.

Example 20: (Z)-Isopropyl7-((1R,2R,3R,5S)-3,5-dihydroxy-2-((R)-5-phenyl-3-((((2-(prop-2-yn-1-yl)pent-4-yn-1-yl)oxy)carbonyl)oxy)pentyl)cyclopentyl)hept-5-enoate

To a solution of 2-(prop-2-yn-1-yl)pent-4-yn-1-ol (716.9 mg, 5.87 mmol)and triphosgene (877.3 mg, 2.96 mmol) in anhydrous DCM (10 mL), pyridine(0.62 mL, 608.8 mg, 7.70 mmol) was added according to Method 4 outlineabove to give 2-(prop-2-yn-1-yl)pent-4-yn-1-yl carbonochloridate as aclear colourless oil (897.7 mg, 83% yield).

To a solution of example 9 (82.6 mg, 0.17 mmol) in anhydrous pyridine (3mL), 2-(prop-2-yn-1-yl)pent-4-yn-1-yl carbonochloridate (68.4 mg, 0.37mmol) was added according to Method 5 outlined above. The crude mixturewas dissolved in methanol (5 mL) and stirred at room temperature for 16h. The residue was purified on the automated flash chromatography using0%-100% EtOAc in pet. spirit gradient elution to give the title compoundas a clear colourless oil (21.9 mg, 23% yield). ¹H NMR (400 MHz, CDCl₃)δ 7.34-7.24 (m, 2H), 7.23-7.11 (m, 3H), 5.48-5.30 (m, 2H), 4.99 (hept,J=6.3 Hz, 1H), 4.83-4.71 (m, 1H), 4.22 (dd, J=6.2, 1.3 Hz, 2H), 4.15(bs, 1H), 3.91 (bs, 1H), 2.80-2.54 (m, 2H), 2.47-2.38 (m, 4H), 2.38-2.24(m, 7H), 2.21-2.05 (m, 4H), 2.02 (t, J=2.7 Hz, 2H), 2.00-1.75 (m, 5H),1.75-1.61 (m, 4H), 1.55-1.24 (m, 3H), 1.23 (s, 3H), 1.21 (s, 3H). ¹³CNMR (101 MHz, CDCl₃) δ 173.60, 155.07, 141.39, 129.85, 129.31, 128.58,128.52, 128.44, 126.14, 78.84, 78.68, 74.79, 70.70, 68.50, 67.78, 66.48,52.99, 51.83, 42.60, 36.45, 35.91, 34.15, 32.85, 31.73, 29.37, 27.02,26.77, 25.03, 21.96, 21.76, 19.84.

Example 21: 2-(Prop-2-yn-1-yl)pent-4-yn-1-yl4-(((((R)-1-((1R,2R,3S,5R)-3,5-dihydroxy-2-((Z)-7-isopropoxy-7-oxohept-2-en-1-yl)cyclopentyl)-5-phenylpentan-3-yl)oxy)carbonyl)oxy)benzoate

To a solution of 2-(prop-2-yn-1-yl)pent-4-yn-1-yl 4-hydroxybenzoate(660.0 mg, 2.72 mmol) and triphosgene (423.4 mg, 1.43 mmol) in anhydrousDCM (15 mL), pyridine (0.31 mL, 267.7 mg, 3.64 mmol) was added accordingto Method 4 outlined above to give 2-(prop-2-yn-1-yl)pent-4-yn-1-yl4-((chlorocarbonyl)oxy)benzoate as a clear colourless oil (633.0 mg, 76%yield). To solution of example 9 (156.3 mg, 0.31 mmol) in anhydrouspyridine (8 mL), 2-(prop-2-yn-1-yl)pent-4-yn-1-yl4-((chlorocarbonyl)oxy)benzoate (296.8 mg, 0.97 mmol) was addedaccording to Method 5 outlined above. The crude mixture was dissolved inmethanol (5 mL) and stirred at room temperature for 16 h. The residuewas purified on the automated flash chromatography using 0%-100% EtOAcin pet. spirit gradient elution to give the title compound as a clearcolourless oil (102.2 mg, 47% yield). ESI-MS: m/z 723 ([M+Na]⁺) ¹H NMR(400 MHz, CDCl₃) δ 8.17-7.98 (m, 2H), 7.35-7.24 (m, 5H), 7.24-7.08 (m,3H), 5.50-5.32 (m, 2H), 5.00 (hept, J=6.3 Hz, 1H), 4.93-4.79 (m, 1H),4.42 (d, J=6.1 Hz, 2H), 4.18 (s, 1H), 3.93 (s, 1H), 2.89-2.63 (m, 2H),2.48 (dd, J=6.5, 2.6 Hz, 4H), 2.42-2.24 (m, 4H), 2.24-1.84 (m, 13H),1.84-1.61 (m, 4H), 1.61-1.45 (m, 1H), 1.45-1.28 (m, 2H), 1.23 (s, 3H),1.21 (s, 3H). ¹³C NMR (101 MHz, CDCl₃) δ 173.57, 165.56, 154.86, 152.95,141.18, 131.40, 130.01, 129.25, 128.68, 128.47, 127.77, 126.29, 121.18,80.09, 78.94, 77.36, 74.84, 70.73, 67.80, 66.00, 53.10, 51.91, 42.71,36.58, 35.79, 34.15, 32.79, 31.74, 29.42, 27.06, 26.80, 25.04, 21.99,20.18.

Example 22: (Z)-2-(Prop-2-yn-1-yl)pent-4-yn-1-yl7-((1R,2R,3R,5S)-3,5-dihydroxy-2-((R,E)-3-hydroxy-4-(3-(trifluoromethyl)phenoxy)but-1-en-1-yl)cyclopentyl)hept-5-enoate

A solution of travoprost free acid (316.5 mg, 0.69 mmol) in anhydrousTHF (10 mL) was added dropwise into a solution mixture of2-(prop-2-yn-1-yl)pent-4-yn-1-ol (97.2 mg, 0.79 mmol), HBTU (288.5 mg,0.76 mmol) and triethylamine (0.38 mL, 276.3 mg, 2.73 mmol) in anhydrousDCM (5 mL) according to the procedure outlined in Method 2 above. Thecrude residue was purified on the automated flash chromatography using0%-20% MeOH in DCM gradient elution to give the title compound as aclear colourless viscous oil (29.0 mg, 7.5% yield). ESI-MS: m/z 608([M+2Na]⁺). ¹H NMR (400 MHz, CDCl₃) δ 7.44-7.36 (m, 1H), 7.25-7.20 (m,1H), 7.18-7.12 (m, 1H), 7.12-7.06 (m, 1H), 5.83-5.61 (m, 2H), 5.50-5.32(m, 2H), 4.63-4.47 (m, 1H), 4.26-4.17 (m, 1H), 4.15 (d, J=6.2 Hz, 2H),4.07-3.90 (m, 3H), 2.78-2.46 (m, 2H), 2.46-2.25 (m, 8H), 2.25-2.04 (m,11H), 2.01 (t, J=2.6 Hz, 2H), 1.87-1.77 (m, 1H), 1.77-1.48 (m, 4H). ¹³CNMR (101 MHz, CDCl₃) δ 173.80, 158.77, 135.25, 133.27, 131.91, 130.22,129.87, 129.43, 129.20, 122.67, 118.22, 118.03 (q, J_(C-F)=3.8 Hz),111.62 (q, J_(C-F)=3.7 Hz), 78.25, 73.23, 72.23, 70.85, 70.64, 65.31,56.20, 50.68, 43.10, 36.38, 33.63, 31.07, 26.74, 25.81, 24.87, 20.00.

Example 23: (Z)-Isopropyl7-((1R,2R,3R,5S)-3,5-dihydroxy-2-((R,E)-3-((2-(prop-2-yn-1-yl)pent-4-ynoyl)oxy)-4-(3-(trifluoromethyl)phenoxy)but-1-en-1-yl)cyclopentyl)hept-5-enoate

A solution of example 11 (124.6 mg, 0.22 mmol) in anhydrous DCM (3 mL)was added dropwise to a solution of 2-(prop-2-yn-1-yl)pent-4-ynoic acid(33.9 mg, 0.25 mmol), DCC (52.9 mg, 0.26 mmol) and DMAP (8.4 mg, 0.07mmol) in anhydrous DCM (4 mL) according to Method 1b outlined above. Theresidue was dissolved in methanol (5 mL) and stirred at room temperaturefor 16 h. The crude residue was purified on the automated flashchromatography using 0%-100% EtOAc in pet. spirit gradient elution togive the title compound as a clear colourless oil (74.0 mg, 54% yield).ESI-MS: m/z 663 ([M+2Na]⁺). ¹H NMR (400 MHz, CDCl₃) δ 7.39 (t, J=8.0 Hz,1H), 7.22 (d, J=7.7 Hz, 1H), 7.14 (d, J=11.3 Hz, 1H), 7.10-6.99 (m, 1H),5.86-5.73 (m, 1H), 5.73-5.58 (m, 2H), 5.44-5.31 (m, 2H), 4.99 (hept,J=6.3 Hz, 1H), 4.24-4.17 (m, 1H), 4.17-4.05 (m, 2H), 4.03-3.86 (m, 1H),2.85-2.73 (m, 1H), 2.72-2.53 (m, 4H), 2.44-2.21 (m, 4H), 2.21-2.00 (m,7H), 1.98 (t, J=2.6 Hz, 1H), 1.87-1.75 (m, 1H), 1.73-1.60 (m, 2H),1.60-1.48 (m, 1H), 1.25 (s, 3H), 1.21 (s, 3H). ¹³C NMR (101 MHz, CDCl₃)δ 173.57, 171.62, 158.67, 137.95, 132.20, 131.87, 130.20, 130.17,128.94, 125.38, 118.24, 118.03 (q, J=3.7 Hz), 111.60 (q, J=3.7 Hz),78.20, 73.28, 73.12, 69.40, 67.81, 56.35, 50.61, 43.17, 43.00, 34.10,26.76, 25.84, 24.96, 21.97, 21.96, 20.06, 20.04.

Example 24: (Z)-7-((1R,2R,3R,5S)-3,5-Dihydroxy-2-((R)-3-hydroxy)-5phenylpentyl)cyclopentyl)hept-5-enoic acid-2-prop-2-yn-1-yl)pent-4-ynoicanhydride

A mixture of latanoprost (0.1 g, 0.23 mmol), imidazole (0.157 g, 2.3mmol) and tert-butyldimethylsilylchloride (0.174 g, 1.15 mmol) in DMF(0.7 mL) was stirred at room temperature for 16 h. The reaction wasquenched by addition of 10% aq citric acid (2.8 mL). The mixture wasextracted with tert-butylmethylether (3×5 mL), the combined organicphase was washed with 10% NaHCO₃ dried over anhydrous Na₂SO₄, filteredand concentrated in vacuo. The residue was purified by flashchromatography using 0%-20% EtOAc in pet. spirit gradient elution togive (Z)-Isopropyl7-((1R,2R,3R,5S)-3,5-bis((tert-butyldimethylsilyl)oxy)-2-((R)-3-((tert-butyldimethylsilyl)oxy)-5-phenylpentyl)cyclopentyl)hept-5-enoateas a clear colourless oil (0.168 g, 94% yield).

To the tri-TBS protected latanoprost solution (505 mg, 0.652 mmol) inMeOH (10 mL), stirred under N₂, H₂O (1.0 mL) was added, followed byLiOH.H₂O (359 mg, 14.99 mmol). After stirring over three days, thereaction mixture was quenched with 5:3 mixture of saturated aqueousNH₄Cl and 2M aqueous NaHSO₄ (20 mL), and extracted with EtOAc (20 mL).The phases were separated, further aqueous NaHSO₄ (2M, 10 mL) was addedto the aqueous phase, and the mixture was extracted with EtOAc (20 mL).the combined organic phases was washed with a mixture of 2:1 saturatedaqueous NH₄Cl and 2M aqueous NaHSO₄ (30 mL), dried over anhydrousNa₂SO₄, filtered and concentrated in vacuo, to give(Z)-7-((1R,2R,3R,5S)-3,5-bis((tert-butyldimethylsilyl)oxy)-2-((R)-3-((tert-butyldimethylsilyl)oxy)-5-phenylpentyl)cyclopentyl)hept-5-enoicacid as a clear colourless oil (471 mg, 98% yield). ¹H NMR (400 MHz,CDCl₃) δ 7.27 (dt, J=6.5, 1.7 Hz, 2H), 7.21-7.14 (m, 3H), 5.48 (dt,J=7.7, 7.2 Hz, 1H), 5.34 (dt, J=10.8, 7.2 Hz, 1H), 4.14-3.98 (m, 1H),3.85-3.61 (m, 2H), 2.73-2.54 (m, 2H), 2.41-2.26 (m, 2H), 2.23-2.00 (m,5H), 1.86-1.62 (m, 5H), 1.62-1.22 (m, 6H), 0.94-0.85 (m, 27H), 0.05(ddd, J=10.9, 6.2, 3.8 Hz, 18H). ¹³C NMR (101 MHz, CDCl₃) δ 177.87,142.84, 130.43, 128.79, 128.48, 128.46, 125.79, 77.36, 77.16, 76.69,72.88, 72.08, 50.35, 48.56, 44.41, 39.36, 34.06, 33.38, 31.82, 27.71,26.73, 26.11, 26.03, 25.67, 24.83, 18.33, 18.23, 18.06, −3.91, −4.13,−4.20, −4.22, −4.59, −4.84.

A solution of tri-TBS protected latanoprost free acid (1.0 eq) inanhydrous DCM (4 mL) was added dropwise to a solution of2-(prop-2-yn-1-yl)pent-4-ynoic acid (1.1 eq.), DCC (1.04 eq.) and DMAP(0.01 eq.) in anhydrous DCM (4 mL) according to Method 1b outlinedabove. The crude residue was purified on the automated flashchromatography using 0%-100% EtOAc in pet. spirit gradient elution togive(Z)-7-((1R,2R,3R,5S)-3,5-bis((tert-butyldimethylsilyl)oxy)-2-((R)-3-((tert-butyldimethylsilyl)oxy)-5-phenylpentyl)cyclopentyl)hept-5-enoicacid-2-prop-2-yn-1-yl)pent-4-ynoic anhydride.

A solution of tri-TBS latanoprost anhydride (1 eq.) and Bu₄NF (1 Msolution in THF, 5.0 eq.) can be stirred for 16 h at room temperatureand concentrated in vacuo. A solution of the residue in CH₂Cl₂ may bewashed with 10% aq citric acid, dried over Na₂SO₄, filtered andconcentrated in vacuo. The residue can be purified by automated flashchromatography using 0%-100% EtOAc in pet. spirit gradient elution inorder to give the title compound.

Example 25: (Z)-Isopropyl7-((1R,2R,3R,5S)-5-hydroxy-2-((R)-3-hydroxy-5-phenylpentyl)-3-((2-(prop-2-yn-1-yl)pent-4-ynoyl)oxy)cyclopentyl)hept-5-enoate

Latanoprost and Novozyme 435 are dried under vacuum for 3 h. AnhydrousTHF and vinyl 2-(prop-2-yn-1-yl)pent-4-ynoate are added. The reactionmixture may be heated at 64° C. for 16 h. The reaction may be quenchedwith chloroform and filtered. The solvent can then be removed in vacuoin order to give the title compound.

Example 26:(S)-1-(tert-Butylamino)-3-((4-morpholino-1,2,5-thiadiazol-3-yl)oxy)propan-2-yl(2-(prop-2-yn-1-yl)pent-4-yn-1-yl) carbonate

To a stirring solution of timolol free base (506.0 mg, 1.6 mmol) andtriethylamine (0.27 mL, 0.20 mmol) in anhydrous DCM (5 mL), a solutionof 2-(prop-2-yn-1-yl)pent-4-yn-1-yl carbonochloridate (368.4 mg, 2.00mmol) in anhydrous DCM (5 mL) was added dropwise at 00° C. The reactionmixture was stirred at room temperature for 24 h. The mixture wasextracted and washed with saturated aqueous NaHCO₃ and saturated brine.The organic phase was dried over anhydrous Na₂SO₄, filtered,concentrated and dried in vacuo. The crude residue was purified on theautomated flash chromatography using 0%-60% EtOAc in pet. spiritgradient elution to give the title compound as a clear colourless oil(206.3 mg, 28% yield). ESI-MS: m/z 465 (M⁺). ¹H NMR (400 MHz, CDCl₃) δ5.08 (qd, J=5.9, 3.1 Hz, 1H), 4.62 (ddd, J=18.4, 11.7, 5.0 Hz, 2H),4.25-4.16 (m, 2H), 3.83-3.71 (m, 4H), 3.56-3.39 (m, 4H), 2.92-2.78 (m,2H), 2.44-2.30 (m, 4H), 2.24-2.08 (m, 1H), 2.06-1.90 (m, 2H), 1.06 (s,9H). ¹³C NMR (101 MHz, CDCl₃) δ 154.59, 153.32, 149.78, 80.60, 76.54,70.72, 70.70, 70.02, 68.67, 66.52, 50.32, 47.80, 42.65, 36.32, 28.96,19.74, 19.73.

Example 27:(S)-1-(tert-Butylamino)-3-((4-morpholino-1,2,5-thiadiazol-3-yl)oxy)propan-2-yl-2-(prop-2-yn-1-yl)pent-4-ynoate

To a stirring solution of timolol free base (1.0 g, 3.16 mmol) inanhydrous DCM (25 mL), 2-(prop-2-yn-1-yl)pent-4-ynoic acid (0.4317 g,3.17 mmol), triethylamine (0.89 mL, 0.647 g, 2.02 mmol) and BOP-Cl(0.8131 g, 3.19 mmol) were added according to the procedure outlined inMethod 3. The reaction mixture was stirred at room temperature for 16 h.The crude residue was purified by automated flash chromatography using0%-70% EtOAc in pet. spirit gradient elution to give the title compoundas a clear colourless oil (0.8145 g, 59% yield). ESI-MS: m/z 435.3([M+H]⁺). ¹H NMR (400 MHz, CDCl₃) δ 5.40-5.25 (m, 1H), 4.66-4.57 (m,2H), 3.87-3.73 (m, 4H), 3.57-3.41 (m, 4H), 2.85 (t, J=9.5 Hz, 2H),2.82-2.72 (m, 1H), 2.72-2.53 (m, 4H), 2.02-1.91 (m, 2H), 1.53-1.44 (m,1H), 1.09 (s, 9H). ¹³C NMR (101 MHz, CDCl₃) δ 171.86, 153.52, 149.93,80.45, 80.41, 73.09, 70.91, 70.80, 70.25, 66.67, 50.92, 47.98, 43.28,42.84, 28.89, 20.16, 20.04.

Example 28:(S)-1-(4-(2-(Cyclopropylmethoxy)ethyl)phenoxy)-3-isopropylamino)propan-2-yl-2-(prop-2-yn-1-yl)pent-4-ynoate

To a stirring solution of betaxolol (0.971 g, 3.16 mmol) in anhydrousDCM (25 mL), 2-(prop-2-yn-1-yl)pent-4-ynoic acid (0.43 g, 3.17 mmol),triethylamine (0.88 mL, 0.64 g, 2.02 mmol) and BOP-Cl (0.804 g, 3.19mmol) were added according to the procedure outlined in Method 3 above.The reaction mixture was stirred at room temperature for 16 h. The cruderesidue was purified by automated flash chromatography using 0%-50%EtOAc in pet. spirit gradient elution to give the title compound as aclear colourless oil (0.679 g, 50% yield.). ESI-MS: m/z 426.3 (M⁺+H).

Example 29:1-((((2-(prop-2-yn-1-yl)pent-4-yn-1-yl)oxy)carbonyl)oxy)ethyl(Z)-7-((1R,2R,3R,5S)-3,5-dihydroxy-2-((R)-3-hydroxy-5-phenylpentyl)cyclopentyl)hept-5-enoate

1-Chloroethyl (2-(prop-2-yn-1-yl)pent-4-yn-1-yl) carbonate

1-Chloroethyl chloroformate (4.70 mL, 43.4 mmol) was added dropwise to asolution of 2-(prop-2-yn-1-yl)pent-4-yn-1-ol (2.649 g, 21.7 mmol) inanhydrous pyridine (50 mL) at 0° C. The reaction mixture was allowed towarm to room temperature and stirred for a further 2 days. The solventwas removed under reduced pressure. The residual was extracted withethyl acetate and washed with water and brine. The organic phase wasthen dried over Na₂SO₄, filtered and concentrated and dried in vacuo.The crude residue was purified on the automated flash chromatographyusing 0%-50% EtOAc in pet. spirit gradient elution to give the titlecompound as a clear colourless liquid (1.1907 g, 24% yield). ¹H NMR (400MHz, CDCl₃) δ 6.43 (q, J=5.8 Hz, 1H), 4.31 (d, J=6.1 Hz, 2H), 2.48-2.36(m, 4H), 2.25-2.14 (m, 1H), 2.03 (t, J=2.6 Hz, 2H), 1.84 (d, J=5.8 Hz,3H).

To a 0° C. solution of latanoprost free acid (702.4 mg, 1.80 mmol) inDMF (5 mL) was added K₂CO₃ (506.3 mg, 3.66 mmol). After 5 mins asolution of 1-chloroethyl (2-(prop-2-yn-1-yl)pent-4-yn-1-yl) carbonate(1.367 g, 5.98 mmol) in DMF (20 mL) was added via cannula and theresultant solution was allowed to warm to room temperature and stirredfor 5 days. EtOAc and sat. aq. NH₄Cl were added, the product wasextracted (EtOAc), washed (H₂O, then brine), dried (Na₂SO₄), filteredand concentrated under reduced pressure. Flash chromatography (20%-100%EtOAc/petrol gradient elution) gave1-((((2-(prop-2-yn-1-yl)pent-4-yn-1-yl)oxy)carbonyl)oxy)ethyl(Z)-7-((1R,2R,3R,5S)-3,5-dihydroxy-2-((R)-3-hydroxy-5-phenylpentyl)cyclopentyl)hept-5-enoate(643.4 mg, 1.10 mmol, 61%) as a colourless viscous oil. R_(f)=0.60(EtOAc); ¹H NMR (400 MHz, CDCl₃) δ 7.30-7.27 (m, 2H), 7.23-7.17 (m, 3H),6.76 (q, J=5.4 Hz, 1H), 5.51-5.35 (m, 2H), 4.25 (d, J=6.2 Hz, 2H), 4.16(m, 1H), 3.95 (m, 1H), 3.67 (m, 1H), 2.80 (m, 1H), 2.68 (m, 1H),2.41-2.09 (m, 11H), 2.02 (t, J=2.6 Hz, 2H), 1.87 (t, J=3.0 Hz, 2H),1.82-1.55 (m, 8H), 1.51 (d, J=5.4 Hz, 3H), 1.43-1.31 (m, 2H); LCMS:m/z=605.3 ([M+Na]⁺).

Using the procedures described the following monomers shown in Table 4may be prepared.

Example Drug Linking Point Linkage Alkyne/azide precursor 30 LTP 15-OHCarbonate

31 LTP 1-COOH Ester

32 LTP 15-OH Carbonate

33 LTP 1-COOH Ester

34 LTP 1-COOH Ester

35 LTP 15-OH Carbonate

36 TVP 15-OH Carbonate

37 TVP 15-OH Carbonate

38 LTP 1-COOH Ester

39 LTP 1-COOH Ester

40 LTP 15-OH Carbonate

41 TIM OH Ester

42 TIM OH Ester

43 TIM OH Carbonate

44 TVP 1-COOH Ester

45 TAF 1-COOH Ester

46 BIM 1-COOH Ester

Production Example Method Monomer 30 Method 5

31 Method 2

32 Method 2

33 Method 2

34 Method 2

35 Method 5

36 Method 5

37 Method 5

38 Method 2

39 Method 5

40 Method 5

41 Method 3

42 Method 3

43 As per Example 26

44 As per Example 29

45 As per Example 29

46 As per Example 29

LTP = latanoprost BIM = bimatoprost TVP = travoprost TAF = tafluprostTIM = timolol

Preparation of Polymer-Bioactive Agent Conjugates Preparation ofCo-monomers

Co-Monomer Methods

Method 6: Reaction of Alcohols with Isocyanates

To a solution of isocyanate monomer (1 eq.) in anhydrous solvent isadded the alcohol derivative (>2 eq.) and dibutyltin dilaurate (cat.,˜0.05 eq). The reaction is stirred at rt under an argon atmosphere for24 h or until the reaction is complete. The mixture is concentrated invacuo to yield the desired product.

Method 7: Azidation of Alkyl Halides, Alkyl Tosylates or Alkyl Mesylates

To a solution of alkyl halide/tosylate/mesylate (1 eq.) in anhydrous DMFis added NaN₃ (5 eq.) and the reaction mixture stirred at 60° C. for 24h or until the reaction is complete. The resultant precipitate wasremoved via filtration and the filtrate was concentrated in vacuo. Theresulting residue is washed with DCM and filtered before concentratingin vacuo to give the desired product.

Method 8: Reaction of Acid Chlorides with Alcohols or Amines

To a solution of acid chloride (1 eq.) in anhydrous solvent at 0° C. isadded an excess of the relevant alcohol or amine (≧2 eq.), DMAP and anappropriate amine base. The solution is allowed to gradually warm to rtand stirred for 48 h or until the reaction is complete. The crudereaction mixture is washed (0.1 M NaHCO₃, followed by 0.1 M HCl), dried(MgSO₄) and concentrated under reduced pressure.

Example 47: Synthesis of (S)-ethyl2,6-bis(((3-azidopropoxy)carbonyl)amino)hexanoate

Ethyl 2,6-diisocyanatohexanoate (ELDI) (1.00 g, 4.42 mmol) and3-chloro-1-propanol (1.04 g, 11.1 mmol) in anhydrous DCM (10 mL) werereacted in the presence of a catalytic amount of dibutyltin dilaurateaccording to the procedure described in Method 6 above to yield(S)-ethyl 2,6-bis(((3-chloropropoxy)carbonyl)amino)hexanoate as a clearoil (1.37 g, 3.30 mmol, 75%).

A solution of (S)-ethyl2,6-bis(((3-chloropropoxy)carbonyl)amino)hexanoate (1.37 g, 3.31 mmol)and NaN₃ (1.07 g, 16.5 mmol) in DMF (20 mL) was reacted according to theprocedure outlined in Method 7 above to give (S)-ethyl2,6-bis(((3-azidopropoxy)carbonyl)amino)hexanoate as an oil (1.33 g,3.10 mmol, 94%). ¹H NMR (400 MHz, d₁-CDCl₃) δ_(H) 1.28 (t, 3H, J=6.9Hz), 1.39-1.72 (m, 6H), 1.81-1.93 (m, 4H), 3.15 (q, 2H, J=7.2 Hz), 3.36(q, 4H, J=6.4 Hz), 4.13-4.23 (m, 6H), 4.29-4.34 (m, 1H), 4.72 (m, 1H),5.26 (d, 1H, J=8.0 Hz).

Example 48: Synthesis of bis(3-azidopropyl) hexane-1,6-diyldicarbamate

1,6-diisocyanatohexane (HDI) (2.00 g, 11.9 mmol) and 3-chloro-1-propanol(4.50 g, 47.5 mmol) in anhydrous DCM (20 mL) were reacted in thepresence of a catalytic amount of dibutyltin dilaurate according to theprocedure described in Method 6 above to yield bis(3-chloropropyl)hexane-1,6-diyldicarbamate as a clear oil (4.20 g, 11.8 mmol, 99%). Asolution of bis(3-chloropropyl) hexane-1,6-diyldicarbamate (4.20 g, 11.8mmol) and NaN₃ in DMF (20 mL) was reacted according to the procedureoutlined in Method 7 above to give bis(3-azidopropyl)hexane-1,6-diyldicarbamate as a white solid (3.86 g, 10.4 mmol, 88%). ¹HNMR (400 MHz, d₁-CDCl₃) δ_(H) 1.32-1.35 (m, 4H), 1.48-1.52 (m, 4H), 1.85(p, 4H, 6.8 Hz), 3.14 (q, 4H, J=6.8 Hz), 3.36 (t, 4H, J=6.4 Hz), 4.19(t, 4H, J=6.0 Hz), 4.68 (t, 1H, J=0.8 Hz).

Example 49: Synthesis of 3-azidopropyl 2-azidoacetate

Chloroacetyl chloride (2.00 g, 17.7 mmol), was reacted with3-chloro-1-propanol (3.35 g, 35.4 mmol), DMAP and pyridine (2.10 g, 26.5mmol) in DCM (15 mL) according to the procedure outlined in Method 8above. The crude material was purified by bulb-to-bulb distillation (65°C./0.5 Mbar) to yield 3-chloropropyl 2-chloroacetate as a clear oil(1.10 g, 6.43 mmol, 36%). A solution of 3-chloropropyl 2-chloroacetate(1.10 g, 6.43 mmol) and NaN₃ (4.18 g, 64.3 mmol) in DMF (20 mL) wasreacted according to the general procedure outlined in Method 7 above togive the desired product 3-azidopropyl 2-azidoacetate.

Example 50: Synthesis of 2-azido-N-(3-azidopropyl)acetamide

Chloroacetyl chloride (1.00 g, 8.85 mmol), was reacted with3-chloro-1-propan-1-amine hydrochloride (2.30 g, 17.7 mmol), DMAP (54.1mg, 0.443 mmol) and triethylamine (2.69 g, 26.6 mmol) in DCM (10 mL)according to the procedure outlined in Method 8 above to yield2-chloro-N-(3-chloropropyl)acetamide as a clear oil (0.381 g, 2.24 mmol,25%). A solution of 2-chloro-N-(3-chloropropyl)acetamide (0.381 g, 2.24mmol) and NaN₃ (1.45 g, 22.4 mmol) in DMF (10 mL) was reacted accordingto the general procedure outlined in Method 7 above to give the desiredproduct 2-azido-N-(3-azidopropyl)acetamide as a brownish oil (0.215 g,1.17 mmol, 52%). ¹H NMR (400 MHz, d₁-CDCl₃) δ_(H) 1.77 (p, 2H, J=6.4Hz), 3.37 (m, 4H), 3.98 (s, 2H).

Example 51: Synthesis of (S)-ethyl2,6-bis(((prop-2-yn-1-yloxy)carbonyl)amino)hexanoate

Ethyl 2,6-diisocyanatohexanoate (ELDI) (1.00 g, 4.42 mmol) and propargylalcohol (0.620 g, 11.0 mmol) in anhydrous DCM (10 mL) were reacted inthe presence of a catalytic amount of dibutyltin dilaurate according tothe procedure described in Method 6 above. The solution was passedthrough an aluminium oxide column before concentrating under reducedpressure to yield (S)-ethyl2,6-bis(((prop-2-yn-1-yloxy)carbonyl)amino)hexanoate as a clear oil(1.24 g, 3.66 mmol, 83%). ¹H NMR (400 MHz, d₁-CDCl₃) δ_(H) 1.25 (t, 3H,J=7.2 Hz), 1.39-1.83 (m, 6H), 2.45-2.48 (m, 2H), 3.15 (q, 2H, J=6.8 Hz),3.36 (q, 4H, J=6.4 Hz), 4.16 (q, 2H, J=7.2 Hz), 4.28-4.33 (m, 1H),4.65-4.68 (m, 4H), 4.94 (m, 1H), 5.47 (d, 1H, J=8.0 Hz)

Example 52: PEG3000-Dilysine Diazide Co-Monomer

A mixture of ethyl 2,6-diisocyanatohexanoate (ELDI) (1.51 g, 6.67 mmol)and PEG3000 (2.0 g, 0.67 mmol) in anhydrous DCM (25 mL) was reactedaccording to the procedure outlined in Method 6. The crude material wasprecipitated several times in Et₂O and dried in vacuo to give aPEG3000-dilysine dicarbamate intermediate product as a white solid (1.8g). ¹H NMR and MALDI-TOF analysis showed quantitative incorporation ofELDI onto both ends of PEG3000.

The above intermediate (0.726 g, 0.210 mmol) was treated with3-chloropropanol (0.199 g, 2.10 mmol) in anhydrous DCM (50 mL) accordingto the procedure outlined in Method 6. The crude material wasprecipitated several times in Et₂O and dried in vacuo to give thePEG3000-dilysine dichloropropanolintermediate as a white solid (0.710g). ¹H NMR and MALDI-TOF analysis confirmed the end group modifications.

The above dichloro intermediate (0.710 g, 0.223 mmol) was treated withNaN₃ (0.31 mg, 4.76 mmol) in DMF (20 mL) according to the procedureoutlined in Method 7. The crude material was precipitated several timesin Et₂O and dried in vacuo to give the PEG3000-dilysine diazidetetracarbamate product as a white solid (0.539 g). ¹H NMR and MALDI-TOFanalysis confirmed the end group modifications.

Example 53: Synthesis of PEG3000-Dilysine Dipropargyl Co-Monomer

A mixture of the PEG3000-dilysine diisocyanate derivative described inExample 48 (1.0 g, 0.29 mmol) and propargyl alcohol (0.162 g, 2.89 mmol)in anhydrous DCM (50 mL) were reacted according to the procedureoutlined in Method 6. The crude material was precipitated several timesin Et₂O and dried in vacuo to give the PEG3000-dilysine dipropargyltetracarbamate product as a white solid (0.486 g). MALDI-TOF analysisconfirmed the end group modifications.

Example 54: Preparation of poly(ethyleneglycol)bis(4-((3S,4S)-(3,4-dimethoxy)azacyclooct-5-yn-1-yl)-4-oxobutanoate)

DCC (2.2 eq) can be added to a solution of a polyethylene glycol (1 eq),4-((3S,4S)-(3,4-dimethoxy)azacyclooct-5-yn-1-yl)-4-oxobutanoic acid (2.5eq) and DMAP (0.1 eq) in DCM in an analogous procedure to that describedin Method 1a. Precipitation of the crude material can provide the titlecompound poly(ethyleneglycol)bis(4-((3S,4S)-(3,4-dimethoxy)azacyclooct-5-yn-1-yl)-4-oxobutanoate).

Example 55: Preparation of (S)-ethyl2,6-bis(((((1R,8S,9r)-1,8-dimethylbicyclo[6.1.0]non-4-yn-9-yl)methoxy)carbonyl)amino)hexanoate

A solution of (S)-ethyl 2,6-diisocyanatohexanoate (1 eq),((1R,8S,9r)-1,8-dimethylbicyclo[6.1.0]non-4-yn-9-yl)methanol (2.2 eq)and dibutyltin dilaurate (catalytic, ˜0.05 eq.) in anhydrous DCM can bereacted according to the procedure outlined in Method 6. The solvent canbe removed under reduced pressure and flash chromatography of the crudematerial can provide the title compound.

Example 56: Preparation of (S)-ethyl2,6-bis((((1R,8S,9s)-bicyclo[6.1.0]non-4-yn-9-ylmethoxy)carbonyl)amino)hexanoate

A solution of (S)-ethyl 2,6-diisocyanatohexanoate (1 eq),(1R,8S,9s)-bicyclo[6.1.0]non-4-yn-9-ylmethanol (2.2 eq) and dibutyltindilaurate (catalytic, ˜0.05 eq.) in anhydrous DCM can be reactedaccording to the procedure outlined in Method 6. The solvent can beremoved under reduced pressure and flash chromatography of the crudematerial can provide the title compound.

Polymer Synthesis

Method 9: Copper Catalysed Click Reaction

(a) Polymer Conjugate Prepared with Dialkyne-Bioactive Agent ConjugateMonomer.

The dialkyne-bioactive agent conjugate monomer (1 eq.) and a diazideco-monomer (1 eq.) are dissolved in the solvent of choice. The solutionis purged with argon for 30 minutes before copper (II) bromide (CuBr₂)(0.05 mol eq.), PMDETA (0.05 mol eq.) and sodium ascorbate (0.15 moleq.) are added into the solution. The heterogeneous mixture is stirredvigorously overnight under argon atmosphere and at room temperature for24 hours. The reaction mixture is then passed through a column of basicalumina to remove the CuBr₂ catalyst, and then concentrated in vacuobefore being precipitated several times in excess amount of diethylether to afford the desired polymer as solids. The polymer-bioactiveagent conjugates are analysed by ¹H NMR and ¹³C NMR and GPC.

(b) Polymer Conjugate Prepared with Diazide-Bioactive Agent ConjugateMonomer.

The diazide-bioactive agent conjugate monomer (1 eq.) and a dialkyneco-monomer (1 eq.) are dissolved in the solvent of choice. The solutionis purged with argon for 30 minutes before copper (II) bromide (CuBr₂)(0.05 mol eq.), PMDETA (0.05 mol eq.) and sodium ascorbate (0.15 moleq.) are added into the solution. The heterogeneous mixture is stirredvigorously overnight at room temperature until complete consumption ofstarting materials, as indicated by TLC. The mixture is diluted withwater and any precipitate that forms is collected. Purification of theproduct by precipitation from DMF and further purification on SephadexLH-20 gives the title polymer-bioactive agent conjugate. Thepolymer-bioactive agent conjugates are analysed by IR, ¹H NMR and ¹³CNMR and GPC

(c) Linear Click Polymer Conjugate Prepared with Dialkyne-BioactiveAgent Conjugate Monomer with Additives.

The dialkyne-bioactive agent conjugate monomer and diazide co-monomer 1and co-monomer 2 are dissolved in the solvent of choice while keeping anequimolar ratio between the number of alkyne units and azide units. Thesolution is purged with argon for 30 minutes before copper (II) bromide(CuBr₂) (0.05 mol eq.), PMDETA (0.05 mol eq.) and sodium ascorbate (0.15mol eq.) are added into the solution. The heterogeneous mixture isstirred overnight under argon atmosphere and at room temperature for 24hours. The reaction mixture is then passed through a column of basicalumina to remove the CuBr₂ catalyst, and then concentrated in vacuobefore being precipitated several times in excess of diethyl ether toafford the desired polymer a solid. The polymer-bioactive agentconjugates are analysed by ¹H NMR and GPC.

(d) Polymer Conjugate Prepared with Alkyne-Azide-Bioactive AgentConjugate Monomer (Drug Monomer Only)

The alkyne-azide bioactive agent conjugate monomer (1 eq.) is dissolvedin the solvent of choice. The solution is purged with argon for 30minutes before copper (II) bromide (CuBr₂) (0.05 mol eq.), PMDETA (0.05mol eq.) and sodium ascorbate (0.15 mol eq.) are added into thesolution. The heterogeneous mixture is stirred vigorously overnightuntil complete consumption of starting materials, as indicated by TLC.The mixture is diluted with water and any precipitate that forms iscollected. Purification of the product by precipitation from DMF andfurther purification on Sephadex LH-20 gives the title polymer-bioactiveagent conjugate. The polymer-bioactive agent conjugates are analysed byIR, ¹H NMR and ¹³C NMR and GPC

(e) Polymer Conjugate Prepared with Alkyne-Azide-Bioactive AgentConjugate Monomer (and Co-Monomer)

The alkyne-azide-bioactive agent conjugate monomer (1 eq.) and analkyne-azide co-monomer (1 eq.) are dissolved in the solvent of choice.The solution is purged with argon for 30 minutes before copper (II)bromide (CuBr₂) (0.05 mol eq.), PMDETA (0.05 mol eq.) and sodiumascorbate (0.15 mol eq.) are added into the solution. The heterogeneousmixture is stirred vigorously overnight until complete consumption ofstarting materials, as indicated by TLC. The mixture is diluted withwater and any precipitate that forms is collected. Purification of theproduct by precipitation from DMF and further purification on SephadexLH-20 gives the title polymer-bioactive agent conjugate. Thepolymer-bioactive agent conjugates are analysed by IR, ¹H NMR and ¹³CNMR and GPC.

(f) Polymer Conjugate Prepared with Dialkyne-Bioactive Agent ConjugateMonomer.

The dialkyne bioactive agent conjugate monomer (1 eq), a 4-arm PEGtetraazide co-monomer (0.5 eq), and sodium ascorbate (0.45 eq) aredissolved in the solvent of choice (0.5 mL) in a 4 mL vial equipped witha magnetic stirrer bar. A stock solution containing CuBr₂ (0.15 eq) andPMDETA (0.15 eq) in the solvent of choice (2 mL) is prepared and 0.2 mLis added to the monomers mixture under a nitrogen atmosphere. The vialwas sealed with a rubber septum, stirred at room temperature undernitrogen for 24 h during which time gelation occurred. The gel wasremoved and dialysed in acetonitrile (3×1 L) and dried under highvacuum.

Method 10: Ruthenium-Catalyzed Click Reaction

The 1,5 disubstituted 1,2,3 triazole containing polymers can be formedusing a procedure described in Zhang et al. J. Am. Chem. Soc., 2005, 127(46), pp 15998-15999,

(a) Polymer Conjugate Prepared with Dialkyne-Bioactive Agent ConjugateMonomer

The dialkyne-bioactive agent conjugate monomer (1 eq.), a diazideco-monomer (1 eq.) and Cp*RuCl(PPh₃)₂ is dissolved in the solvent ofchoice (benzene, THF, DMF or dioxane) and allowed to stir at 60-80° C.until reaction is complete. Progress of the reaction is monitored by ¹HNMR or TLC. The mixture is diluted with water and any precipitate thatforms is collected. Purification of the product by precipitation fromdiethyl ether and further purification on Sephadex LH-20 gives the titlepolymer-bioactive agent conjugate. The polymer-bioactive agentconjugates are analysed by IR, ¹H NMR and ¹³C NMR and GPC.

(b) Polymer Conjugate Prepared with Diazide-Bioactive Agent ConjugateMonomer

The diazide-bioactive agent conjugate monomer (1 eq.) and a dialkyneco-monomer (1 eq.) and Cp*RuCl(PPh₃)₂ are dissolved in the solvent ofchoice (benzene, THF, DMF or dioxane) and allowed to stir at 60-80° C.until reaction is complete. Progress of the reaction is monitored by ¹HNMR or TLC. The mixture is diluted with water and any precipitate thatforms is collected. Purification of the product by precipitation fromdiethyl ether and further purification on Sephadex LH-20 gives the titlepolymer-bioactive agent conjugate. The polymer-bioactive agentconjugates are analysed by IR, ¹H NMR and ¹³C NMR and GPC.

(c) Polymer Conjugate Prepared with Azide-Alkyne-Bioactive AgentConjugate Monomer

The azide-alkyne-bioactive agent conjugate monomer and Cp*RuCl(PPh₃)₂are dissolved in the solvent of choice (benzene, THF DMF or dioxane) andallowed to stir at 60-80° C. until reaction is complete. Progress of thereaction is monitored by ¹H NMR or TLC. The mixture is diluted withwater and any precipitate that forms is collected. Purification of theproduct by precipitation from diethyl ether and further purification onSephadex LH-20 gives the title polymer-bioactive agent conjugate. Thepolymer-bioactive agent conjugates are analysed by IR, ¹H NMR and ¹³CNMR and GPC.

Method 11: Strain Promoted Azide Alkyne Cycloaddition

a) Polymer Conjugate Prepared with Dicycloalkyne-Bioactive AgentConjugate Monomer and Diazide Co Monomer

The dicycloalkyne-bioactive agent conjugate monomer substrate and thediazide monomer substrate can be dissolved separately in a solvent(CH₃CN or DMF) and mixed in a 1:1 ratio. The reaction mixture can bestirred for 12 h at room temperature. The mixture may be diluted withwater and any precipitate that forms collected. Purification of theproduct by precipitation from DMF and diethyl ether and furtherpurification on Sephadex LH-20 will give the title polymer-bioactiveagent conjugate.

b) Polymer Conjugate Prepared with Diazide-Bioactive Agent ConjugateMonomer and Dialkyne (Cyclooctyne) Co-Monomer

A diazide-bioactive agent conjugate monomer and a dicycloalkyneco-monomer can be dissolved separately in solvent (CH₃CN or DMF) andreacted using the same procedure as described for Method 12 a)

Using the above methods the following polymers in Table 5 were prepared.

TABLE 5 Examples of Click Polymers Drug- Drug- Co- Production monomer 1monomer 2 Monomer 1 Co-Monomer 2 Method Example Drug (mg) (mg (mg) (mg)(solvent) Characterisation 57 LTP 13 — ELDN₃ 9(a) Mw = 24.5 kDa, PDI =(23) (14.1) (DMF) 1.33 solid (25 mg) 58 LTP 12 — ELDN₃ 9(a) Mw = 36.5kDa, PDI = (108)  (87.4) (DMF) 1.57, solid (101.9 mg) 59 LTP 12 — ELDN₃PEG3000 diN₃ 9(a) Mw = 36.2 kDa, (108)  (78.6) (65.5) (DMF) PDI = 1.61solid (137.1 mg) 60 LTP 13 — ELDN₃ 9(a) Mw = 72.3 kDa, PDI = (113) (69.8) (DMF) 2.20 Solid (151 mg) 61 LTP 17 — ELDN₃ 9(a) Mw = 14.7 kDa,PDI = (100)  (72.7) (DMF) 1.39 foam (106 mg) 62 LTP 17 — ELDN₃ PEG3000diN₃ 9(b) Mw = 35.5 kDa, PDI = (100)  (65.4) (54.4) (DMF) 1.14 solid(150 mg) 63 LTP 13 — ELDN₃ 9(a) Mw = 71.3 kDa, PDI = (150)  (91.9)(DMF)) 2.29 foam (211 mg) 64 LTP 12 — ELDN₃ PEG400diN₃ 9(b) Mw = 13.9kDa, PDI =  (101.4) (73.8) (9.92) (DMF) 1.32 foam 65 LTP 12 — ELDN₃PEG400diN₃ 9(b) Mw = 26.9 kDa, PDI =  (100.7) (40.7) (49.2) (DMF) 1.65foam 66 LTP 12 — HDN₃ 9(a) Mw = 37.7 kDa, PDI =   (94.8) (71.0) (DMF)1.83 foam 67 LTP 19 — ELDN₃ 9(a) Mw = 6.85 kDa, PDI = (100)  (62.8)(DMF) 1.10 solid 68 LTP 14 — — PEG400diN₃ 9(a) Mw = 13.9 kDa, PDI =  (88.5) (69.6) (DMF) 1.32 soft green tacky solid 69 LTP 17 — PEG400diN₃9(a) Mw = 15.5 kDa, PDI = (96) (84.4) (DMF) 1.37 solid 70 LTP 20 —PEG400diN₃ 9(a) Mw = 27.4 kDa, PDI =   (51.5) (42.9) (DMF) 1.67 solid 71LTP 21 — PEG400diN₃ 9(a) Mw = 28.1 kDa, PDI =   (83.4) (57.6) (DMF) 1.68solid 72 LTP 18 — PEG400diN₃ 9(a) Mw = 20.6 kDa, PDI =   (78.2) (51.4)(DMF) 1.48 solid 73 LTP and 13 Tim-O- PEG400diN₃ 9(a) Mw = 18.0 kDa, PDI= Timolol   (52.5) carbonate- (77.8) (DMF) 1.42 dialkyne 26 solid (37.3)74 LTP 13 — PEG400diN₃ 9(a) Mw = 21.3 kDa, PDI =   (82.9) (61.5) (DMF)1.51 solid 75 TVP 23 — PEG400diN₃ 9(a) Mw = 21.3 kDa, PDI = (70) (54.7)(DMF) 1.52 solid 76 LTP 15 — PEG400diN₃ 9(a) Mw = 21.5 kDa, PDI =  (68.2) (45.2) (DMF) 1.51 solid 77 Timolol 27 — ELDN₃ 9(a) Mw = 26.9kDa, PDI = (100)  (98.6) (DMF) 1.64 78 LTP 14 — ELDN₃ 9(a) Mw = 51.3kDa, PDI = (100)  (69.7) (DMF) 2.00 79 LTP and 18 Tim-O-ester- ELDN₃9(a) Mw = 9.83 kDa, PDI = Timolol (55.3) dialkyne 27 (64.3) (DMF) 1.15(32.6) 80 LTP 14 — HDN₃ 9(a) Mw = 84.1 kDa, PDI = (100)  (60.3) (DMF)2.09 81 Timolol 26 — ELDN₃ 9(a) Mw = 36.5 kDa, PDI = (144)  (124) (DMF)1.20 foam 82 LTP 29 — — (N₃—C₄H₈—COO- 9(f) gel  (73.7) PEG₅₀₀-)₄-C (DMF)(156.4) 83 LTP 29 — — (N₃—C₃H₆—NHCOO- 9(f) gel  (211.4) PEG₅₀₀-)₄-C(DMF) (457.4) 84 LTP 29 — — (N₃—C₃H₆—NHCOO- 9(f) gel  (109.9)PEG₂₀₀-)₄-C (DMF) (116.2) 85 LTP 29 — — (N₃—C₃H₆—NHCOO- 9(f) gel  (76.5)PEG₂₀₀-)₄-C (DMF) (79.1) 86 LTP 29 — — (N₃-PEG₅₀₀)₄-C 9(f) gel  (74.6)(128.7) (DMF) 87 LTP 29 (N₃—C(═CH₂)—CH₂—O—C(O)—C(O)— 9(f) gel  (157.4)PEG₂₀₀₀-)₄-C (DMF) (327.2)

Using the above methods the following polymers may also be prepared.

Method Drug- Co- of Exam- monomer Monomer Synthesis ple Drug conjugateCo-Monomer 1 2 (solvent)  88 LTP 12

—  9(a) (DMF)  89 LTP 12

— 10(a) (DMF)  90 LTP 18

— 10(a) (DMF)  91 LTP 39

—  9(b) (DMF)  92 LTP 39

— 10(b) (DMF)  93 LTP 12

PEG3000 diN₃  9(c) (DMF)  94 LTP 38

—  9(e) (DMF)  95 LTP 38 — —  9(d) (DMF)  96 LTP 38

 9(e) (DMF)  97 TIM LTP 41 38 —  9(e) (DMF)  98 TVP 22 47 —  9(a) (DMF) 99 TVP 23 47 —  9(a) (DMF) 100 TVP 36 47 —  9(a) (DMF) 101 LTP 34 47 —11(a) (DMF) 102 LTP 35 47 — 11(a) (DMF) 103 LIP 39

— 11(b) (DMF) 104 LIP 32

— 11(b) (DMF)

Drug Release Method

Polymer samples were tested for in vitro drug release followingguidelines recommended by the International Organisation ofStandardisation. The samples were placed onto a wire mesh folded into anM shape and suspended in isotonic phosphate buffer (IPB) pH 7.4 or pH8.4 (Table 1), and stirred at 37° C. Aliquots of the receptor solutionwere collected at pre-determined time points until the drug was depletedfrom the polymer.

The amount of drug in the aliquots was quantified by reverse phase highperformance liquid chromatography (HPLC) coupled with UV detection.Analytes were separated on a C18 column with a solvent mixture ofacetonitrile and phosphate buffer (Latanoprost: acetonitrile andphosphate buffer pH 2.5, Latanoprost free acid: acetonitrile andphosphate buffer pH 5.0) or acetonitrile and water with triethylamineand phosphoric acid (Timolol). The rate of drug release from variouspolymers is shown in Table 6. It is anticipated that the otherpolymer-drug conjugates of the invention will release drug in a similarfashion.

TABLE 6 Drug release from polymers. Release study Example Buffer pH forRate no. release study Drug [μg/10 mg/24 hrs] 58 7.4 Latanoprost free0.59 8.4 acid 2.10 59 7.4 Latanoprost free 1.91 8.4 acid 4.91 60 7.4Latanoprost free 0.85 acid 64 7.4 Latanoprost free 2.27 acid 65 7.4Latanoprost free 5.05 acid 66 7.4 Latanoprost free 1.68 acid 81 7.4Timolol 1527 68 7.4 Latanoprost free 58.73 8.4 acid 135.23 71 8.4Latanoprost 1.55 74 7.4 Latanoprost free 16.48 8.4 acid 47.51 76 7.4Latanoprost free 36.37 acid 83 7.4 Latanoprost free 11.65 acid 82 7.4Latanoprost free 10.07 acid 84 7.4 Latanoprost free 2.55 acid 85 7.4Latanoprost free 3.15 acid

It is to be understood that various other modifications and/oralterations may be made without departing from the spirit of the presentinvention as outlined herein.

Throughout this specification and the claims which follow, unless thecontext requires otherwise, the word “comprise”, and variations such as“comprises” and “comprising”, will be understood to imply the inclusionof a stated integer or step or group of integers or steps but not theexclusion of any other integer or step or group of integers or steps.

The reference in this specification to any prior publication (orinformation derived from it), or to any matter which is known, is not,and should not be taken as an acknowledgment or admission or any form ofsuggestion that that prior publication (or information derived from it)or known matter forms part of the common general knowledge in the fieldof endeavour to which this specification relates.

1. A polymer-bioactive agent conjugate comprising: a polymer backbonecomprising a plurality of triazole moieties; and a plurality ofreleasable prostaglandin analogues covalently bonded to and pendant fromthe polymer backbone from the 1-position of the prostaglandin analoguevia an ester linking group.
 2. A polymer-bioactive agent conjugateaccording to claim 1, comprising a moiety of formula (I):

where: T represents a triazole moiety; Q is independently selected ateach occurrence and may be present or absent and when present representsa linking group; R is an optionally substituted linear or branchedhydrocarbon and may comprise optionally substituted aromatic hydrocarbonor heteroaromatic hydrocarbon; Z is a cleavable linking group; and D isa releasable prostaglandin analogue of formula Xb

wherein:

represents the point of attachment of the prostaglandin analogue to Z;

represents a double or single bond; Y is optionally substituted C₄ toC₁₀ hydrocarbyl or optionally substituted C₄ to C₁₀ hydrocarbyloxy; R⁹and R¹¹ are hydroxy; and W is hydroxy and U is hydrogen, or W and U areboth fluoro, or W and U together form oxo.
 3. A polymer-bioactive agentconjugates according to claim 2 comprising a moiety of formula (Ib):

where: T at each occurrence represents a triazole moiety; Q isindependently selected at each occurrence may be present or absent andwhen present represents a linking group; R is an optionally substitutedlinear or branched hydrocarbon and may include optionally substitutedaromatic hydrocarbon and heteroaromatic hydrocarbon; Z¹ and Z² are eachcleavable linking groups that may be the same or different; and D¹ andD² are each releasable prostaglandin analogues that may be the same ordifferent and are of formula Xb.
 4. A polymer-bioactive agent conjugateaccording to claim 2, wherein the polymer backbone comprises at leastone moiety selected from formula (IIa) and (IIb):


5. A polymer-bioactive agent conjugate according to claim 2, wherein thepolymer backbone comprises at least one moiety selected from formula(IIIa) and (IIIb):


6. A polymer-bioactive agent conjugate according to claim 2, wherein thelinker Z comprises a moiety of formula:—C(O)O—C₁ to C₁₈ alkylene-O—.
 7. A polymer—prostaglandin analogueconjugate according to claim 6, wherein the linker group Z is of formula(R) —C(O)O—C₁ to C₁₂alkylene-O— (D) wherein (R) indicates the end of thegroup bonded to the R group and (D) indicates the end of the groupbonded to the prostaglandin.
 8. A polymer bioactive conjugate accordingto claim 6, wherein the linker group Z is of formula:(R) —OC(O)O—C₁ to C₁₂ alkylene-O-(D) wherein (R) indicates the end ofthe group bonded to the R group and (D) indicates the end of the groupbonded to the prostaglandin.
 9. A polymer bioactive conjugate accordingto claim 6, wherein the linker group Z is of formula:

wherein R¹ is selected from the group consisting of hydrogen and C₁ toC₁₁ alkyl.
 10. A polymer bioactive conjugate according to claim 6,wherein the linker group Z is of formula:

wherein R¹ is selected from the group consisting of hydrogen and C₁ toC₁₁ alkyl.
 11. A polymer bioactive conjugate according to claim 2,wherein R is a hydrocarbon of 1 to 6 carbon atoms.
 12. Apolymer-bioactive agent conjugate according to claim 1, which is acopolymer of at least one monomer of formula (IV):

where: X may be the same or different at each occurrence and representsa terminal functional group comprising an alkyne or an azide; Q isindependently selected at each occurrence and may be present or absentand when present, represents a linking group; R is an optionallysubstituted linear or branched hydrocarbon and may comprise optionallysubstituted aromatic hydrocarbon or heteroaromatic hydrocarbon; Z is acleavable linking group; and D is a bioactive agent selected from theprostaglandin analogues of formula Xb:

wherein:

represents the point of attachment of the prostaglandin analogue to Z;

represents a double or single bond; Y is optionally substituted C₄ toC₁₀ hydrocarbyl or optionally substituted C₄ to C₁₀ hydrocarbyloxy; R⁹and R¹¹ are hydroxy; and W is hydroxy and U is hydrogen, or W and U areboth fluoro, or W and U together form oxo and a monomer of formula (V):A-LA]_(n)  (V) where: A may be the same or different at each occurrenceand represents a group comprising a terminal functional group comprisingan alkyne or an azide functionality, wherein said terminal functionalgroup is complementary to the terminal functional group of X; L is anoptionally substituted linker group; and n is an integer and is atleast
 1. 13. A polymer-bioactive agent conjugate according to claim 12,wherein in the monomer of formula (V), L comprises a linker moietyselected from the group consisting of optionally substituted linear orbranched aliphatic hydrocarbon, optionally substituted carbocyclyl,optionally substituted heterocyclyl, optionally substituted aryl,optionally substituted heteroaryl, and an optionally substitutedpolymeric segment.
 14. A polymer-bioactive agent conjugate according toclaim 12 wherein L is a biodegradable polymer comprising at least onebiodegradable moiety selected from the group consisting of an ester, anamide, a urethane, a urea and a disulfide moiety.
 15. Apolymer-bioactive agent conjugate according to claim 12, wherein in themonomer of formula (V), n is 1, 2 or
 3. 16. A polymer-bioactive agentconjugate according to claim 12, wherein in the monomer of formula (IV),Q is present and each Q-X is independently selected from the followinggroup:


17. A polymer-bioactive agent conjugate according to claim 12, whereinin the monomer of formula (IV), each Q-X is a group of formula (VII):

where: X is a terminal functional group comprising an alkyne or an azidefunctionality; and m is an integer in the range of from 0 to
 10. 18. Apolymer-bioactive agent conjugate according to claim 12, wherein thelinker Z comprises a moiety of formula:—C(O)O—C₁ to C₁₈ alkylene-O—.
 19. A polymer—prostaglandin analogueconjugate according to claim 18, wherein the linker group Z is offormula(R) —C(O)O—C₁ to C₁₂alkylene-O— (D) wherein (R) indicates the end of thegroup bonded to the R group and (D) indicates the end of the groupbonded to the prostaglandin.
 20. A polymer bioactive conjugate accordingto claim 18, wherein the linker group Z is of formula:(R) —OC(O)O—C₁ to C₁₂ alkylene-O— wherein (R) indicates the end of thegroup bonded to the R group and (D) indicates the end of the groupbonded to the prostaglandin.